Process for preparing a dispersing component comprising an inorganic oxide sol

ABSTRACT

A process for preparing a dispersing component of an inorganic oxide sol which involves dehydrating an aqueous inorganic oxide sol by adding an azeotropic solvent to the aqueous inorganic sol to form an azeotropic mixture, carrying out azeotropic distillation and then surface-treating the dispersing component of the inorganic oxide sol with a silane coupling agent.

This application is a divisional application of application Ser. No.08/758,062, filed Nov. 27, 1996 (U.S. Pat. No. 6,022,919), which is acontinuation-in-part of International Application No. PCT/JP96/01114,filed Apr. 24, 1996 (not published in English), the entire contents ofwhich are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel coating composition, the morepreferable coating composition containing a dispersing component of aninorganic oxide sol prepared by a specific process for preparing, thespecific process for preparing the dispersing component of the inorganicoxide sol, and the more preferable coating composition prepared by aspecific process for preparing and the specific process for preparingthe coating composition. More particularly, it relates a novel coatingcomposition comprising a ceramic ingredient which gives paint filmhaving excellent stain resistance, stain-removing property, weatheringresistance, light resistance, chemical resistance, moisture resistanceand appearance and is excellent in environment friendliness and safety.Further, it relates a process for preparing the coating composition anda process for preparing a dispersing component of an inorganic oxide solused in the coating composition.

2. Background Information

In recent years, many oil droplets and dusts have existed in air byenvironmental changes such as air pollution. As the result, someproblems have occurred, among which paint film on buildings, automobilesand the like are easier to be stained than former and it's stain isdifficult to remove. Thus, it has been desired that paint films haveresistance to the stain, i.e. stain resistance and property to removestain from stained paint films, i.e. stain-removing property. In suchcircumstances, it is desired to produce coating compositions which givepaint films having excellent stain resistance, stain-removing property,weathering resistance, light resistance, gloss, appearance, waterresistance and chemical resistance and is excellent in environmentfriendliness and safety property.

Convenient coating compositions having stain resistance which have beenused, comprise a fluorine-containing resin as a main component. Thestain resistance of the coating compositions is attributed to excellentweathering resistance of the fluorine-containing resin. Thefluorine-containing resin manifest the performance by (1) stabilitycaused by larger bond energy between fluorine atom and carbon atomcompared with that between hydrogen atom and carbon atom and (2) waterrepellency and oil repellency caused by larger atomic radius of fluorineatom compared with that of hydrogen atom and lower surface free energyattributed to lower polarizability between fluorine atoms(0.68×10⁻²⁴cc).

However, there are some problems that the fluorine-containing resin isrestricted in the range of resin designation because of differentpolymerization reactivity compared with general acrylic monomers,attributed to stronger electronegativity of fluorine atom and expensive,and some fluorine-containing monomer is bad in solubility to solvents.Further, there is fear that bad influence to environment may be causedby the production of hydrogen fluoride at stage of waste disposal of thepaint film comprising the fluorine-containing resin. Accordingly, thoughthe fluorine-containing resin manifests excellent performance, theseproblems such as the restriction of cost and use and bad influence tothe environment at the waste disposal have been highlighted.

A coating composition, which gives paint films having weatheringresistance with an acrylic polyol produced by reacting a polymerizablemonomer having stability to ultraviolet rays as essential component, isnear recently suggested as a coating composition having excellentweathering resistance (Laid Open Japanese Patent Application PublicationHei 1-261409). But, there is no description about stain resistance inthis publication. Also, a coating composition comprising a partialcondensate of an organic silicon compound and a specific silicaparticulate as the coating composition having excellent stain resistance(Laid Open Japanese Patent Application Publication Hei 2-3468). But,there is no specific description about the resin component used in thecoating composition in the publication. Further, a coating compositioncomprising an acrylic polyol resin, a binder, inorganic organo sol and asolvent is suggested (Laid Open Japanese Patent Application PublicationHei 4-173882). But, though the coating composition is improved in stainresistance, weathering resistance and light resistance a little, thecoating composition has a defect that the stain-removing property isinsufficient.

Thus, the coating composition, which gives paint films having stainresistance, stain-removing property, weathering resistance and lightresistance, has been not developed.

The present invention accordingly has an object to provide coatingcompositions which give paint film having excellent stain resistance,stain-removing property, weathering resistance, light resistance, waterresistance, chemical resistance, and appearance and are excellent inenvironment friendliness and safety property. Another object of theinvention is to provide processes for preparing the coating compositionsand processes for preparing a dispersing component of an inorganic oxidesol used in the coating compositions.

Extensive investigations undertaken by the present inventors to developthe coating composition having properties described above lead to adiscovery that the objects can be achieved by a coating compositioncomprising a specific acrylic resin, a polyisocyanate compound or anaminoplast resin and a specific ceramic ingredient, that more excellentspecified properties can be obtained by mixing the specific ceramicingredient with the specific acrylic resin at a final stage of thepolymerization process of the acrylic resin, and that most excellentspecified properties can be obtained by using the ceramic ingredienttreated with a specific silane coupling agent.

The present invention was completed on the basis of the discoveriesdescribed above.

SUMMARY OF THE INVENTION

Thus, the present invention provides a coating composition comprises (A)a resin having a glass transition temperature of 50 to 120° C., a numberaverage molecular weight of 2,000 to 100,000, a hydroxyl value of 50 to150 mgKOH/g and an acid value of 1 to 25 mgKOH/g, which is produced bycopolymerizing 10 to 90 percent by weight of (a) a (meth) acrylic acidester of an alkyl alcohol of 1 to 12 carbon atoms, 10 to 50 percent byweight of (b) a polymerizable double bond-containing and hydroxylgroup-containing monomer, 0.1 to 10 percent by weight of (c) apolymerizable double bond-containing and carboxyl group-containingmonomer, 0 to 20 percent by weight of (d) styrene, 0 to 20 percent byweight of (e) acrylonitrile and 0 to 10 percent by weight of (f) otherpolymerizable double bond-containing monomer, (B) at least one compoundselected from the group consisting of a polyisocyanate compound havingtwo or more unblocked isocyanate groups and/or blocked isocyanate groupsin the molecule and an aminoplast resin, (C) a dispersing component ofat least one inorganic oxide sol selected from the group consisting ofan aluminum oxide sol, a silica sol, a zirconium oxide sol and anantimony oxide sol, wherein an amount of a nonvolatile matter of thesaid ingredient (C) is 5 to 60percent by weight based on a total amountof nonvolatile matter.

Further, the present invention provides a process for preparing acoating composition which comprises copolymerizing 10 to 90 percent byweight of (a) a (meth) acrylic acid ester of an alkyl alcohol of 1 to 12carbon atoms, 10 to 50 percent by weight of (b) a polymerizable doublebond-containing and hydroxyl group-containing monomer, 0.1 to 10 percentby weight of (c) a polymerizable double bond-containing and carboxylgroup-containing monomer, 0 to 20 percent by weight of (d) styrene, 0 to20 percent by weight of (e) acrylonitrile and 0 to 10 percent by weightof (f) other polymerizable double bond-containing monomer to produce aresin (A) having a glass transition temperature of 50 to 120° C., anumber average molecular weight of 2,000 to 100,000, a hydroxyl value of50 to 150 mgKOH/g and an acid value of 1 to 25 mgKOH/g, adding adispersing component of at least one inorganic oxide sol (C) selectedfrom the group consisting of an aluminum oxide sol, a silica sol, azirconium oxide sol and an antimony oxide sol into a polymerizationliquid containing the resin (A) in 5 to 60 percent by weight asnonvolatile matter based on a total amount of nonvolatile matter afterfinishing of the copolymerization of the resin (A) to produce aorganic-inorganic composite, and then mixing at least one compound (B)selected from the group consisting of a polyisocyanate compound havingtwo or more isocyanate unblocked groups and /or blocked isocyanategroups in the molecule and an aminoplast resin with theorganic-inorganic composite.

Also, the invention provides a process for preparing a dispersingcomponent of an inorganic oxide sol dispersed in a solvent whichcomprises dehydrating a dispersing component of an aqueous inorganicoxide sol by azeotropic distillation with an azeotropic solvent to waterand then surface-treating the dispersing component with a silanecoupling agent.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

Preferable embodiment for practicing the invention The resin used as theresin (A) in the coating composition of the invention has a glasstransition temperature of 50 to 120° C. When the glass transitiontemperature is less than 50° C. , the obtained paint film hasinsufficient hardness and the paint film having excellent weatheringresistance is difficult to obtain. When the glass transition temperatureis more than 120° C., the operation efficiency in coating process is badand the obtained paint film is lower in appearance such as distinctnessof image and gloss. The lower stain-removing property, which is a defectof the coating composition suggested in Laid Open Japanese PatentApplications Hei 4-173882, is improved by controlling the glasstransition temperature in the range described above. Preferable glasstransition temperature is in the range of 50 to 100° C. in view ofhardness, appearance and stain-removing property of the paint film andoperation efficiency.

The resin has a number average molecular weight of 2,000 to 100, 000.When the number average molecular weight is less than 2,000, theobtained paint film has insufficient weathering resistance. When thenumber average molecular weight is more than 100,000, the operationefficiency is bad in coating process. The number average molecularweight of the resin (A) is preferably 2,200 to 70,000, more preferably2,200 to 40,000 in view of weathering resistance of the paint film andoperation efficiency.

The resin has a hydroxyl value of 50 to 150 mgKOH/g. When the hydroxylvalue is less than 50 mgKOH/g, the obtained paint film has insufficientcrosslinking density and the paint film having excellent stainresistance and excellent stain-removing property is difficult to obtain.When the hydroxyl value is more than 150 mgKOH/g, cracks in the paintfilm is easily caused because contraction stress become large byexcessive density of the structure of the paint film at formation of thepaint film and is impossible to be relaxed. The hydroxyl value ispreferably in the range of 50 to 130 mgKOH/g in view of stainresistance, stain-removing property and the inhibition of cracks of thepaint film.

The resin has an acid value of 1 to 25 mgKOH/g. When the acid value isless than 1 mgKOH/g, the dispersibility of pigments in an enamel paintsystem becomes bad so that objectionable points such as precipitationand aggregation of pigments are caused in storage of the coatingcomposition. When the acid value is more than 25 mgKOH/g, the trend ofthe extreme decrease in the pot life of the coating composition isobserved. The acid value is preferably 2 to 20 mgKOH/g in view ofdispersibility of pigments, storage stability and pot life of thecoating composition.

The resin of ingredient (A) is produced by copolymerizing essentially(a) a (meth) acrylic acid ester of an alkyl alcohol of 1 to 12 carbonatoms, (b) a polymerizable double bond-containing and hydroxylgroup-containing monomer and (c) a polymerizable double bond-containingand carboxyl group-containing monomer, and optionally (d) styrene, (e)acrylonitrile and (f) other polymerizable double bond-containingmonomer.

The (meth) acrylic acid ester of an alkyl alcohol of 1 to 12 carbonatoms (hereinafter called “acrylic ester”) of component (a) used as theessential monomer component is used in ratio of 10 to 90 percent byweight based on total weight of the all monomers. The acrylic ester isnecessary and essential component to control the glass transitiontemperature of the paint film. When the alkyl group in the portion ofthe alcohol has carbon atoms of more than 12, the trend of the excessdecrease in the glass transition temperature of the obtained resin isobserved. When the amount of the acrylic ester is less than 10 percentby weight, it is impossible to control the glass transition temperatureof the obtained resin in the range of not less than 50° C. unless othermonomers having lower polymerization reactivity are not used. If othermonomers having lower polymerization reactivity are used, the weatheringresistance of the paint film is decreased. Contrariwise, when theamount- of the acrylic ester is more than 90 percent by weight, thedesired amount of hydroxyl groups and carboxyl groups is not introducedin the resin and the paint film having excellent weathering resistance,stain resistance and stain-removing property is difficult to obtain.

A Preferable amount of the acrylic ester is 35 to 80 percent by weightin order to obtain the paint film having desired and preferableproperties.

The alkyl alcohol of 1 to 12 carbon atoms which constitute the acrylicester of component (a) may be a straight chain alcohol, a branch chainalcohol or an alcohol having a cyclic alkyl group. Examples of acrylicesters of component (a) are, for example, methylmethacrylate,ethylmethacrylate, n-propylmethacrylate isopropylmethacrylate,n-butylmethacrylate, isobutylmethacrylate, t-butylmethacrylate,pentylmethacrylate, hexylmethacrylate cyclohexylmethacrylate 2-ethylhexylmethacrylate adamantylmethacrylate, dodecylmethacrylate,isobornylmethacrylate, methylacrylate, ethylacrylate, n-propylacrylate,isopropylacrylate, n-butylacrylate , isobutylacrylate , t-butylacrylate, pentylacrylate, hexylacrylate, cyclohexylacrylate, 2-ethylhexylacrylate adamantylacrylate, dodecylacrylate,isobornylacrylate. The acrylic esters may be utilized singly or as acombination of two or more members.

The polymerizable double bond-containing and hydroxyl group-containingmonomer of component (b) used as essential monomer component is used inratio of 10 to 50 percent by weight based on total weight of the allmonomers. When the amount is less than 10 percent by weight, it isimpossible to introduce crosslinking points needed in the obtained resinand to obtain the paint film having excellent weathering resistance,stain resistance and stain-removing property. On the other hand, whenthe amount is more than 50 percent by weight, the unreacted hydroxylgroups remain in crosslinking reaction between the obtained resin andingredient (B). Therefore, the water resistance and the moistureresistance are decreased and the decrease of the weathering resistanceof the paint film is caused. Further, the crosslinking density of thepaint film is excessively increased. A preferable amount of the monomerof component (b) is 10 to 30 percent by weight in order to obtain thepaint film having desired properties by introducing the proper number ofcrosslinking points in the resin.

The polymerizable double bond-containing and hydroxyl group-containingmonomer of component (b) has each one or more polymerizable double bondsand one or more hydroxyl groups, preferably one polymerizable doublebond and one hydroxyl group. Examples of the monomer of component (b)is, for example, hydroxyethylmethacrylate, hydroxypropylmethacrylatehydroxybutylmethacrylate, 1, 4 - butandiolmonomethacrylate,e-caprolactone adduct of hydroxyethylmethacrylate, ethylene oxide adductof hydroxyethylmethacrylate, propylene oxide adduct ofhydroxyethylmethacrylate, hydroxyethylacrylate hydroxypropylacrylate,hydroxybutylacrylate, 1, 4 -butandiolmonoacrylate, e-caprolactone adductof hydroxyethylacrylate, ethylene oxide adduct of hydroxyethylacrylate,propylene oxide adduct of hydroxyethylacrylate. The monomers ofcomponent (b) may be utilized singly or as a combination of two or moremembers.

The polymerizable double bond-containing and carboxyl group-containingmonomer is essentially used in ratio of 0.1 to 10 percent by weightbased on total weight of the all monomers. When the amount is less than0.1 percent by weight, the acid value of the obtained resin isexcessively decreased, the dispersibility of pigments in an enamel paintsystem becomes bad and objectionable points such as precipitation andaggregation of pigments are caused in storage of the coatingcomposition. When the amount is more than 10, the trend of the extremedecrease in storage stability and pot life of the coating composition isobserved. The amount of component (c) is preferably 1 to 5 percent byweight, more preferably 1 to 3 percent by weight in view ofdispersibility, storage stability and pot life of the coatingcomposition.

The polymerizable double bond-containing and carboxyl group-containingmonomer of component (c) has each one or more polymerizable double bondsand one or more carboxyl groups, preferably one polymerizable doublebond and one or two carboxyl groups.

Examples of component (c) are, for example, methacrylic acid, acrylicacid, itaconic acid, mesaconic acid, maleic acid, fumaric acid,ω-carboxy-polycaprolactone (n=2) monoacrylate (for example ALONIXM-5300, a product of TOA GOUSEI CHEMICAL INDUSTRY L.T.D.), phthalic acidmonohydroxyethylacrylate (for example ALONIX M-5400, a product of TOAGOUSEI CHEMICAL INDUSTRY L.T.D.), acrylic acid dimer (for example ALONIXM-5600, a product of TOA GOUSEI CHEMICAL INDUSTRY L.T.D.). These may beused singly or as a combination of two or more members.

Styrene of component (d) is not essential component and is optionallyused to improve appearance such distinctness of image of the paint film.When styrene is used, the amount of styrene is in ratio of not more than20 percent by weight based on the total weight of all monomers. When theamount of styrene is more than 20 percent by weight, the trend of thedecrease in the weathering resistance, stain resistance andstain-removing property of the paint film is observed. The amount ofstyrene is preferably 1 to 18 percent by weight in view of the balanceof appearance such distinctness of image, weathering resistance, stainresistance and stain-removing property of the paint film.

Acrylonitrile of component (e) is not essential component and isoptionally used to improve the adhesion of the paint film to a substrateand impact resistance. When acrylonitrile is used, the amount ofacrylonitrile is in ratio of not more than 20 percent by weight based onthe total weight of all monomers. When the amount of acrylonitrile ismore than 20 percent by weight, the trend of the decrease in theweathering resistance, stain resistance and stain-removing property ofthe paint film is observed. The amount of acrylonitrile is preferably 1to 18 percent by weight in view of the balance of the adhesion of thepaint film to the substrate, weathering resistance, stain resistance andstain-removing property of the paint film.

Another polymerizable double bond-containing monomer of component (f) isnot essential component and is optionally used according to substratesand the purpose of use in the designation of the paint film. When othermonomer is used, the amount is not more than 10 percent by weight. Whenthe amount of other monomer is more than 10 percent by weight, it isdifficult to obtain the paint film having desired properties. The amountof other monomer of component (f) is preferably 1 to 7 percent byweight, when component (f) is used.

Another polymerizable double bond-containing monomer of component (f)has one or more polymerizable double bonds, preferably one polymerizabledouble bond.

Examples of other monomers of component (f) is, for example, PHOSMER (aproduct of UNICHEMICAL L.T.D.), glycydilmethacrylate, glycidylacrylate,allylmethacrylate, allylacrylate, 3,4 -epoxycyclohexylmethylmethacrylate3,4 epoxycyclohexylmethylacrylate, phenylmethacrylate, phenylacrylate,a-methylstyrene, p-vinyltoluene, methacrylamide, acrylamide, N,N-dimethylmethacrylamide, N,N-dimethylacrylamide, methacrylic acid-1, 2,2, 6, 6-pentamethyl-4-piperidinyl ester, acrylic acid-1, 2, 2, 6, 6-pentamethyl-4-piperidinyl ester, methacrylic acid-2, 2, 6,6-tetramethyl-4 -piperidinyl ester, acrylic acid-2, 2, 6,6-tetramethyl-4-piperidinyl ester ; aliphatic vinylethers such asethylvinylether isopropylvinylether, n-propylvinylether,n-butylvinylether isobutylvinylether, 2-ethylhexylvinylether andcyclohexylvinylether 2, 3 - dihydrofuran, 3, 4 -dihydro-2H-pyrantrimethoxysilylpropylmethacrylate, maleic anhydride, itaconic anhydride,maleic acid ester and fumaric acid ester. These may be utilized singlyor as a combination of two or more members.

The resin of ingredient (A) is obtained by copolymerizing the monomersin the ratio described above. The polymerization method is particularlynot limited. Various convenient polymerization methods such as solutionpolymerization in an organic solvent, suspension polymerization ,emulsion polymerization, bulk polymerization and precipitationpolymerization can be utilized. Also, the embodiment of thepolymerization is particularly not limited. For example, radicalpolymerization, cation polymerization and anion polymerization can beutilized. Preferable the embodiment of the polymerization is radicalpolymerization in view of industrial point. Examples of polymerizationinitiators in radical polymerization are, for example, an organicperoxides such as t-butylhydroperoxide, cumenehydroperoxide,t-butylperoxyneodecanate, t-butylperoxypivalate, t-hexylperoxy-2-ethylhexanoate, methylethylketoneperoxide; and an 4 azo initiators suchas 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis(2-methylpropionitrile) (AIBN) and 2,2′-azobis (2-methylbutironitrile).Of course, other polymerization initiators than the above describedpolymerization initiators can be used. The polymerization initiators maybe utilized singly or as a combination of two or more members.

The polymerization temperature is preferably 60 to 150° C. in general.When the polymerization temperature is less than 60° C., the radicalpolymerizaition initiators are difficult to be decomposed and thepolymerization reaction is difficult to be proceeded. When thepolymerization temperature is more than 150° C., though the radicalpolymerizaition initiators are decomposed to generate radicals byheating, the life time of the radicals is short and a propagationreaction is difficult to be effectively proceeded. The polymerizationtime is indiscriminately not determined because of the influence of thepolymerization temperature and the other conditions, but is generallysufficient at the level of 2 to 6 hours.

At least one compound selected from the group consisting of apolyisocyanate compound having two or more unblocked isocyanate groupsand/or blocked isocyanate groups in the molecule and an aminoplast resinis used as a curing agent of ingredient (B) in the coating compositionof the present invention.

Preferable examples of the polyisocyanate compounds having two or moreisocyanate groups are, for example, compounds called “iscyanate monomer”such as hexamethylenediisocyanate isophoronediisocyanatetolylenediisocyanate diphenylmethanediisocyanate, xylylenediisocyanateand dicyclohexylmethan-4,4′-diisocyanate; and polyisocyanate derivativessuch as biulet compounds , isocyanurate derivatives andtrimethylolpropane adducts thereof. The polyisocyanate compound may beutilized singly or as a combination of two or more members.

The polyblocked isocyanate compound contains the compounds produced byblocking a part or all of the isocyanate groups in the polyisocyanatecompounds described above with a blocking agent. Examples of theblocking agents, for example, e-caprolactam; a ketoxime blocking agentssuch as methylethylketoxime, methylisoamylketoxime andmethylisobutylketoxime; a phenol blocking agents such as phenol, cresol,catechol and nitrophenol; an alcohol blocking agents such as isopropanoland trimethylolpropane; and an active methylene blocking agents such asmalonic acid ester and acetoacetic acid ester. The polyblockedisocyanatecompounds may be utilized singly or as a combination of two or moremembers.

Preferable examples of the aminoplast resins are melamine resin andguanamine resin. The aminoplast resins may be utilized singly or as acombination of two or more members. The aminoplast resins are notrestricted as long as the aminoplast resins have two or more reactivegroups in the molecule. Therefore, the melamine resin and the guanamineresin may have one or more triazine rings in the molecule. The reactivegroups in the resins include preferably methylol group, imino group andan etherificated methylol group with methanol, butanol or the like.

In the coating composition of the present invention, ingredient (A) andingredient (B) are formulated in the following ratio. When ingredient(B) is the polyisocyanate compound having two or more unblockedisocyanate groups and/or blocked isocyanate groups in the molecule, amole ratio of unblocked isocyanate groups and/or blocked isocyanategroups in ingredient (B) to hydroxyl groups in ingredient (A) ispreferably 0.6 to 1.6, more preferably 0.8 to 1.2. When the mole ratiois less than 0.6, a part of the hydroxyl groups in the resin ofingredient (A) may not react and remain in the crosslinking reaction ofthe polyisocyanate compound of ingredient (B) and the resin ofingredient (A), so that the water resistance and moisture resistance ofthe obtained paint film may decrease and further the weatheringresistance of the paint film may cause by the decrease of the waterresistance and moisture resistance. On the other hand, when the moleratio is more 1.6, a part of unblocked isocyanate groups and/or blockedisocyanate groups may not react and remain. In such case, the waterresistance and moisture resistance of the obtained paint film maydecrease so that the weathering resistance of the paint film maydecrease by the decrease of the water resistance and moistureresistance.

When ingredient (B) is the aminoplast resin, the weight ratio of thenonvolatile matter of ingredient (A) to ingredient (B) is preferably inthe range of 97 : 3 to 60 : 40, more preferably in the range of 95: 5 to65: 35, furthermore preferably in the range of 91: 9 to 70: 30. When theamount of the aminoplast resin is less than formulation ratio of 97: 3,the crosslinking density of the paint film is decreased and the desiredproperties such as solvent resistance of the paint film may not beobtained. When the amount of the aminoplast resin is more thanformulation ratio of 60 : 40, objectionable points such as the decreaseof flexibility of the paint film may be caused.

In the coating composition of the present invention, a dispersingcomponent of at least one inorganic oxide sol selected from the groupconsisting of an aluminum oxide sol, a silica sol, a zirconium oxide soland an antimony oxide sol is utilized as a ceramic ingredient ofingredient (C). The preferable inorganic oxide sol is a silica sol.

Many of the inorganic oxide sols are generally supplied as aqueousdispersing system. In the case of the aqueous dispersing system, whenthe coating composition is a waterborne system, the dispersing systemcan be utilized as it is. When the coating composition is a solutionsystem of an organic solvent, the methods such as phase conversion intothe organic solvent can be utilized. Preferable organic solvents includeketone solvents such as methylisobutylketone and cyclohexanone.

The method of phase conversion into the organic solvent includes themethod that a water-soluble organic solvent is added into the aqueousdispersing component and a operation of distillation and removement ofwater is repeated to proceed the phase conversion into the desiredorganic solvent.

The dispersing component of a silica sol can be produced by addingsilicon tetrahalide into water, by adding acid into aqueous sodiumsilicate solution and the like. Examples of commercial aqueousdispersing components are SNOWTEX-O (trade name, a product of NissanChemical Industries, Ltd.) and SNOWTEX-N (trade name, a product ofNissan Chemical Industries, Ltd. ). Examples of commercial organicsolvent dispersing components are SNOWTEX-MIBK-ST (trade name, a productof Nissan Chemical Industries Co. Ltd.).

The dispersing component of an inorganic oxide sol is preferably adispersing component of an inorganic oxide sol surface-treated with asilane coupling agent, more preferably a dispersing component of silicasol surface-treated with a silane coupling agent. The surface-treateddispersing component of an inorganic oxide sol can introduce variousfunctional groups on the surface of the particles. Therefore, when thesurface-treated dispersing component is used in the coating compositionof the present invention, the surface-treated dispersing componenteasily bonds with organic components such, as the resin, thepolyisocyanate compound or the aminoplast resin. In such case that theceramic ingredient chemically bonds with the organic component, thecrosslinking of the paint film is tighter than that without chemicalbonds and the stain resistance, stain-removing property and weatheringresistance are improved.

The silane coupling agents include vinyltrimethoxysilanevinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane,methyltrimethoxysilane, methyltriethoxysilane anddimethyldimethoxysilane. The silane coupling agent is preferablymethyltrimethoxysilane, dimethyldimethoxysilane,γ-glycidoxypropyltrimethoxysilane andγ-methacryloyloxypropyltrimethoxysilane, more preferablymethyltrimethoxysilane and dimethyldimethoxysilane. Examples ofcommercial silane coupling agents are A-162, A-163 and AZ-6122 (eachtrade name, a product of NIPPON UNICAR CO., L.T.D.). The silane couplingagents may be utilized singly or as a combination of two or moremembers. When the dispersing component of the inorganic oxide sol issurface-treated with the silane coupling agent, the amount of the silanecoupling agent is preferably 1 to 40 percent by weight, more preferably5 to 30 percent by weight based on the nonvolatile matter of theinorganic oxide sol.

The dispersing component of the inorganic oxide sol surface-treated withthe silane coupling agent is preferably a dispersing component of theinorganic oxide sol produced by dehydrating water contained in anaqueous inorganic oxide sol by azeotropic distillation with anazeotropic solvent to water and then surface-treating the dispersingcomponent with the silane coupling agent. More preferably, thedispersing component of the inorganic oxide sol is a dispersingcomponent of the silica sol. The dispersing component of the inorganicoxide sol produced by the method improves the stain resistance,stain-removing property and weathering resistance of the obtained paintfilm. Further, a coating composition having high nonvolatile matter canbe easily obtained by preparing the coating composition because it ispossible to increase the concentration of the inorganic oxide sol.Therefore, it is possible to select a thinner for controlling theviscosity of the coating composition from various thinners, in broadselection width and to increase the thickness of the paint film incoating.

The azeotropic solvents include a water-soluble alcohol, a water-solublecarboxylic acid ester and a water-soluble cyclic ether.

The water-soluble alcohols include ethanol, n-propylalcohol,i-propylalcohol, n-butylalcohol, i-butylalcohol, sec-butylalcohol,t-butylalcohol, methylcellosolve, ethylcellosolveethyleneglycolmonomethylether, ethyleneglycolmonoethyletherethyleneglycolmono-n-propylether, ethyleneglycolmonobutyletherdiethyleneglycolmonomethylether, diethyleneglycolmonoethylether,diethyleneglycolmonobutylether, 3 -methyl-3 -methoxybutanol,propyleneglycolmonomethylether, ethyleneglycol and propyleneglycol.

The water-soluble carboxylic acid esters include methylacetate andethylacetate. The water-soluble cyclic ethers include 1,4-dioxane.

The azeotropic solvents may be utilized singly or as a combination oftwo or more members.

A water-insoluble solvent also can be used together with a mediation ofthe water-soluble solvent in order to improve the efficiency ofdehydration by azeotropic distillation. The water-insoluble solventsinclude benzene, xylene, toluene, cyclohexanone, diphenylether anddibutylether. The water-insoluble solvent may be utilized singly or as acombination of two or more members. The amount of the water-insolublesolvent is limited in the range in which the sol is not flocculated andgenerally preferably 1 to 10 percent by weight, though the amount isdifferent according to the kind of the water-insoluble solvents.

The dehydration by azeotropic distillation is preferably proceeded withthe dropping of azeotropic solvent. The dehydration by azeotropicdistillation is proceeded in the range of preferably 30 to 100° C., morepreferably 40 to 80° C. The dehydration by azeotropic distillation canbe proceeded under reduced pressure or atmosphere, preferably underreduced pressure. The water content of the inorganic oxide sol dispersedin the azeotropic solvent after the dehydration by azeotropicdistillation is generally preferably not more than 2 percent by weight,more preferably not more than 1 percent by weight. The concentration ofthe dispersing component of the inorganic oxide sol dispersed in theazeotropic solvent after dehydration by azeotropic distillation ispreferably not more than 55 percent by weight, more preferably 25 to 55percent by weight as nonvolatile content.

The surface-treatment with the silane coupling agent can be proceeded bymixing the silane coupling agent with the dispersing component of theinorganic oxide sol dispersed in the azeotropic solvent after thedehydration by azeotropic distillation. The temperature ofsurface-treatment with the silane coupling agent is particularly notlimited, preferably 20 to 100° C., more preferably 30 to 90° C.,furthermore 40 to 80° C.

The water content of the inorganic oxide sol dispersed in the azeotropicsolvent after the surface-treatment with the silane coupling agent isgenerally preferably not more than 1 percent by weight, more preferablynot more than 0.5 percent by weight.

The solvent of inorganic oxide sol dispersed in the azeotropic solventcan be substituted with the desired solvent according to the need. Thesolvents used in solvent substitution include an alcohol describedabove, acetone, methylethylketone, methylisobutylketone, cyclohexanone,dimethylacetoamide and dimethylformamide. The solvent substitution isproceeded in the range of preferably 30 to 120° C., more preferably 40to 110° C., though it is influenced by the kind of the solvents.

In the coating composition of the present invention, the dispersingcomponents of inorganic oxide sol may be utilized singly or as acombination of two or more members. The amount of the nonvolatile matterof the dispersing component of inorganic oxide sol is selected to be 5to 60 percent by weight based on the total amount of nonvolatile matterof ingredient (A), ingredient (B) and ingredient (C). When the amount ofthe nonvolatile matter of the dispersing component of inorganic oxidesol is less than 5 percent by weight to the total amount of nonvolatilematter, the effect of addition of the dispersing component of inorganicoxide sol is not sufficiently obtained and the improvement effect of thestain resistance, stain-removing property and weathering resistance ofthe paint film is not sufficiently obtained. When the amount of thenonvolatile matter of the dispersing component of inorganic oxide sol ismore than 60 percent by weight to the total amount of nonvolatilematter, the trend of the decrease in the flexibility of the paint filmis observed. The amount of the nonvolatile matter of the dispersingcomponent of inorganic oxide sol is preferably 5 to 40 percent by weightagainst the total amount of nonvolatile matter in view of the balance ofstain resistance, stain-removing property, weathering resistance, andflexibility of the paint film.

The average particle diameter of the dispersing component of inorganicoxide sol is preferably not more than 100 nm, more preferably not morethan 50 nm. When the average particle diameter is more than 100 nm,transparency of a clear film decreases and the stain resistance andremoving property of the paint film decrease.

In the coating composition of the present invention, a curing reactioncatalyst may be utilized. When the polyisocyanate compound having two ormore isocyanate groups and/or blocked isocyanate groups in the moleculeis used as ingredient (B) in the coating composition of the presentinvention, the curing reaction catalysts include a tin compound and azinc compound. The tin compounds include tin halides such as tinchloride and tin bromide; organic tin compounds such asdibutyltindiacetate and dibutyltindilaurate. The zinc compounds includezinc halides such as zinc chloride and zinc bromide; organic acid zincsalts such as zinc octanoate and zinclaurate. The tin compound and thezinc compound of the curing reaction catalyst may be utilized singly oras a combination of two or more members and may be utilized togetherwith other curing reaction catalysts. The preferable amount of thecuring reaction catalyst is 0.01 to 5 percent by weight based on thetotal amount of nonvolatile matter in the coating composition. When theamount of the curing reaction catalyst is less than 0.01 percent byweight, the promoting effect of the curing reaction may beinsufficiently exerted. When the amount of the curing reaction catalystis more than 5 percent by weight, the water resistance and moistureresistance of the paint film may be decreased, and the decreases of thestain resistance, removing resistance and weathering resistance of thepaint film may be caused. The more preferable amount of the curingreaction catalyst is 0.01 to 2 percent by weight based on the totalamount of nonvolatile matter of the composition in view of the balanceof the curing rate and the properties of the paint film.

In the coating composition of the present invention, when the aminoplastresin is used as ingredient (B), a curing reaction catalyst for theaminoplast resin may be utilized. The curing reaction catalysts for theaminoplast resin include phosphoric acid curing catalyst, sulfonic acidcuring catalysts such as toluenesulfonic acid and dodecylbenzenesulfonicacid, and the amine-blocked compound thereof. The curing reactioncatalysts may be utilized singly or as a combination of two or moremembers and may be utilized together with other curing reactioncatalysts in order to control the curing time. The preferable additionamount of the curing reaction catalyst for the aminoplast resin is 0.01to 2 percent by weight based on the total amount of nonvolatile matterof the coating composition. With respect to the reason, when the amountof the curing reaction catalyst is less than 0.01 percent by weight, theeffect of the curing reaction catalyst for the aminoplast resin may benot manifested in curing of the coating composition. When the amount ofthe curing reaction catalyst is more than 2 percent by weight, theproperties such as water resistance and moisture resistance of the paintfilm may become bad by the influence of the curing reaction catalystafter forming the paint film and the stain resistance, removingproperties of stain and weathering resistance of the paint film may bedecreased.

When an enamel is produced by compounding the proper pigments, dyes orflake pigments (brightener) in preparing the composition of the presentinvention, the obtained enamel does not lose the essential effect.Therefore, it is possible to give design properties such as thecoloration of the substrate by compounding colored pigments other than aclear coating composition. It is also possible to control the propertiesof the paint film by compounding an extender pigment. These includecolored pigments such as titanium oxide, carbon black, an organicpigment and red iron oxide; colorant such a as glass flake, aluminumflake and mica flake; fillers such as talc; and extender pigments suchas strontium chlomate and barium sulfate.

When the coating composition of the present invention contains thepigment, the amount of the pigment is generally preferably 0.1 to 40percent by weight, more preferably 0.5 to 35 percent by weight.

The preparation methods of the coating composition of the presentinvention are not particularly limited and includes that of the mixingessential components and required various additives in an arbitraryorder and with other various methods. The preferable preparation methodis the following method.

That is the preparation method which is proceeded by using aorganic-inorganic composite obtained by copolymerizing 10 to 90 percentby weight of (a) a (meth) acrylic acid ester of an alkyl alcohol of 1 to12 carbon atoms, 10 to 50 percent by weight of (b) a polymerizabledouble bond-containing and hydroxyl group-containing monomer, 0.1 to 10percent by weight of (c) a polymerizable double bond-containing andcarboxyl group-containing monomer, 0 to 20 percent by weight of (d)styrene, 0 to 20 percent by weight of (e) acrylonitrile and 0 to 10percent by weight of (f) other polymerizable double bond-containingmonomer to produce a resin (A) having a glass transition temperature of50 to 120° C., a number average molecular weight of 2,000 to 100,000, ahydroxyl value of 50 to 150 mgKOH/g and an acid value of 1 to 25mgKOH/g, and adding at least one (C) dispersing component of aninorganic oxide sol selected from the group consisting of an aluminumoxide sol, a silica sol, a zirconium oxide sol and an antimony oxide solinto a polymerization liquid to be 5 to 60 percent by weight as anonvolatile matter of ingredient (C) based on a total amount ofnonvolatile matter of ingredient (A), ingredient (B) and ingredient (C)after finishing of the copolymerization of the resin (A), or by mixingand stabilizing ingredient (C) in the monomers and by copolymerizing themonomers. Particularly, after finishing of the copolymerization toobtain the resin of ingredient (A), the dispersing component of theinorganic oxide sol of ingredient (C) is preferable to be added into thepolymerization liquid under heating or without heating and to bestabilized in dispersion state.

The addition of a diluent is generally conducted to control theconcentration of the resin liquid after the preparation of the resin ofingredient (A) by polymerization. The addition of the dispersingcomponent of the inorganic oxide sol of ingredient (C) is replaced tothe addition of the diluent.

By adding the dispersing component of the inorganic oxide sol into thepolymerization liquid after finishing of the copolymerization of theresin of ingredient (A), it is difficult to cause the aggregation of thedispersing component of the inorganic oxide sol. And, in the case of thefurther addition of the dispersing component of the inorganic oxide solat later stages, it is difficult to cause the aggregation of thedispersing component of the inorganic oxide sol.

In the application of the coating composition, the operation efficiencyof electrostatic coating, transfer efficiency of coating, atomization ofparticulate and appearance of the paint film are extremely improved.Therefore,the operation efficiency in coating process line is extremelyimproved and the appearance of the obtained paint film is very superior.Further, when the concentration of the organic-inorganic compositesolution, in which the ingredient (C) is dispersed and stabilized, isincreased, rise of viscosity is comparably low and high solid coatingcomposition can be easily obtained. The coating composition of thepresent invention is preferable as a coating composition capable todecrease environmental pollution.

As described above, the preferable addition of the dispersing componentof the inorganic oxide sol of ingredient (C) is conducted afterfinishing of the copolymerization of the resin of ingredient (A). Theterm “after finishing of the copolymerization” means “after preparationof the resin of ingredient (A) having a glass transition temperature of50 to 120° C., a number average molecular weight of 2,000 to 100,000, ahydroxyl value of 50 to 150 mgKOH/g and an acid value of 1 to 25mgKOH/g”. The polymerization liquid may contain unreacted monomers.

The addition of the dispersing component of the inorganic oxide sol ofingredient (C) is preferably conducted at the temperature of not morethan the boiling point of the dispersion medium of the inorganic oxidesol of ingredient (C), more preferably conducted at the temperature of10 to 50° C. lower than the boiling point of the medium of the inorganicoxide sol of ingredient (C). The polymerization liquid before theaddition of the dispersing component (C) contains preferably 40 to 80percent by weight, more preferably 50 to 70 percent by weight of theresin material.

In the case of the clear coating composition, preferable preparationmethods of the coating composition include a preparation methodcomprising mixing and stabilizing the dispersing component of theinorganic oxide sol of ingredient (C) in the solvents of polymerizationand then copolymerizing the monomers to produce the resin of ingredient(A) in the same condition described above and uniformly mixing the resin(A) according to the need, the curing agent of ingredient (B) andrequired various additives, and a preparation method comprisingcopolymerizing the monomers to produce the resin of ingredient (A) andthen adding and stabilizing the dispersing component of the inorganicoxide sol in the polymerization liquid under heating or without heatingto produce the organic-inorganic composite solution, in which theinorganic oxide sol is dispersed and stabilized, and uniformly mixingthe resin (A) according to the need, the curing agent of ingredient (B)and required various additives.

In the case of the enamel coating composition, the coating compositionof this invention can be prepared by dispersing the desired pigmenttogether with the resin of ingredient (A) and/or a dispersant and thelike by a dispersing machine and compounding it in the clear coatingcomposition described above. The various additives used according to theneed include colorants such as a dye, a glass flake, an aluminum flakeand mica flake, a filler, a solvent, a pigment dispersant, a flowcontrolling agent, a leveling agent, an antigelling agent, anantioxidant, an ultraviolet absorber, an ultraviolet stabilizer and aradical scavenger.

The curing temperature and time required to curing such coatingcompositions of the present invention are influenced with the kind ofthe ingredients and the reaction catalysts, the curing temperature isgenerally a room temperature to 220° C. and the curing time is generally30 seconds to 10 hours.

The coating compositions of the present invention can be utilized in asingle layer paint film or in multi layers paint film.

The multi layers paint films include that prepared by the coating methodcomprising applying a colored film forming composition on a substrate toform a base coat film and then applying a clear coat film formingcomposition of the this coating composition on the base coat film toform a clear top coat film.

The colored film forming composition of the base coat film comprises aresin binder and a pigment. The resin binders include various binderssuch as a conventional acrylic resin, a polyester resin (containing analkyd resin), a polyurethane resin and melamine resin.

The colored film forming composition of the base coat film can compriseat least one of conventional various additives such as a surface activeagent, a leveling agent, a thixotropic agent, a filler, a defoamingagent, an organic solvent and a catalyst.

The amount of the pigment is preferably 1 to 80 percent by weight, morepreferably 3 to 60 percent by weight in the colored film formingcomposition.

The pigments include various pigments of organic pigments and inorganicpigments. Examples of the pigments include surface treated metallicpigments such as aluminum, copper, brass, bronze, stainless steel, ironoxides of mica form, metallic powders of flake form and mica coated withtitanium dioxide or iron oxides; inorganic pigments such as titaniumdioxide, iron oxides, yellow iron oxide and carbon black; organicpigments such as phthalocyanine blue, phthalocyanine green andquinacridone red pigments; extender pigments such as precipitated bariumsulfate, clay, silica and talc.

The method of applying the coating composition to form the multi layerspaint film includes a method which comprises heating the colored filmforming composition of the base coat film or controlling the viscosityby adding organic solvents or reactive diluents according to the needs,and applying the colored film forming composition on the substrate byconventional coating machines such as air spray, electrostatic airspray, roll coater, flow coater, dip type coating machine and the like,brush, bar coater or applicator in an amount to form a film having driedthickness of 0.5 to 300 μm and curing, in general, in the condition of50 to 300° C. for 5 seconds to 24 hours, followed applying the clearforming composition of the clear coat film on the base coat by the abovemethod in an amount to form a film having dried thickness of 10 to 100μm, preferable 10 to 60 μm and curing, in general, in the condition of50 to 300 ° C. for 5 seconds to 24 hours and the like and a method whichcomprises, in the case of two coat one bake coating, diluting thecolored film forming composition with suitable solvents such as organicsolvents to control the desirable viscosity, applying the base coatcomposition on the substrate by the above method in an amount to form afilm having dried thickness of 5 to 40 μm, preferable 7 to 35 μm,allowing to stand at room temperature to 100 ° C. for 1 to 20 minutes,followed applying the clear forming composition of the clear coat filmon the base coat by the above method in an amount to form a film havingdried thickness of 10 to 100 μm, preferable 10 to 60 μm and curing, ingeneral, in the condition of 50 to 300° C. for 5 seconds to 24 hours andthe like. Preferable method of the application is the application by anair spray in the above methods.

Other multi layers paint film includes that produced by a method whichcomprises applying a colored base coating composition on the substrate,followed by applying a clear coating composition on the uncured coloredbase coat and curing the coats, and then by applying an over clearcoating composition on the clear coat and curing, wherein the clearcoating composition is an acrylic resin-aminoplast resin coatingcomposition and the over clear coating composition is the coatingcomposition of this invention. The colored base coating composition issimilar to that described in the above multi layers paint film.

The acrylic resin-aminoplast resin coating composition can be used asthe clear coating composition applied on the uncured colored base coat.The acrylic resins include a resin produced by copolymerizing (a) a(meth) acrylic acid ester of an alkyl alcohol of 1 to 12 carbon atoms,(b) a polymerizable double bond-containing and hydroxyl group-containingmonomer and (c) a polymerizable double bond-containing and carboxylgroup-containing monomer, and optionally (d) styrene, (e) acrylonitrileand (f) other polymerizable double bond-containing monomer and the like.The preferable aminoplast resins include a melamine resin and aguanamine resin. The aminoplast resin may be utilized singly or in acombination of two or more members. The aminoplast resin has two or morereactive groups in the molecule and is not particularly limited. Thetriazin ring may be one or more in a molecule of the melamine resin andthe guanamine resin. The preferable reactive group in the resinsincludes methylol group, imino group and groups etherificated withmethanol or butanol. The compound ratio of the acrylic resin and theaminoplast resin in the acrylic resin-aminoplast resin coatingcomposition is not particularly limited and preferably 90: 10 to 50: 50,more preferably 80: 20 to 60: 40 in parts by weight.

A curing reaction catalyst for the aminoplast resin can be formulated inthe acrylic resin-aminoplast resin coating composition. Preferableexamples of the curing reaction catalysts for the aminoplast resin are ,for example, a phosphoric acid curing catalyst, sulfonic acid curingagents such as toluenesulfonic acid and dodecylbenzenesulfonic acid andan amine blocked compound thereof. The curing reaction catalysts can beutilized singly or in combination of two or more members and may beutilized together with other compounds in order to control the curingtime. The additional amount of curing reaction catalyst is preferably0.01 to 2 percent by weight based on the total amount of nonvolatilematter in the acrylic resin-aminoplast resin coating composition.

The clear coating composition in the method of preparing the multilayers paint film can comprise additives such as a flow controllingagent, a leveling agent, an antigelling agent, an antioxidant, anultraviolet absorber, an ultraviolet stabilizer and a iradicalscavenger, according to the needs.

The preferable methods of preparing the multi layers paint film includea method which comprises controlling the viscosity by heating thecolored film forming composition of the base coat film or adding organicsolvents or reactive diluents according to the needs, and applying thecolored film forming composition on the substrate by conventionalcoating machines such as air spray, electrostatic air spray, rollcoater, flow coater, dip type coating machine and the like, brush, barcoater or applicator in the amount to form a film having dried thicknessof 5 to 40 μm, preferably 7 to 35 μm and allowing to stand , in general,in the condition of a room temperature to 100 C. for 1 to 20 minutes,followed applying the clear coating composition on the base coat by theabove method in the amount to form a film having dried thickness of 10to 100 μm, preferable 10 to 60 μm and curing, in general, in thecondition of 50 to 300° C. for 5 seconds to 24 hours and the like andthen applying the over clear coating composition on the clear coat bythe above method in the amount to form a film having dried thickness of5 to 50 μm, preferable 5 to 20 μm and then curing, in general, in thecondition of 50 to 300° C. for 5 seconds to 24 hours.

The kind of the substrate to which the coating is applied is notparticularly limited, but various kinds of organic or inorganicsubstrate materials, such as woods, glasses, metals, fabrics, plastics,rug foamed articles, elastomers, papers, ceramics, concretes and gypsumboards, may be utilized. The substrates may be treated on the surfaceand coated with one or more coating compositions.

Coated articles prepared by the coating composition of the presentinvention include buildings, structures, wood articles, metallicarticles, plastics articles, rubber articles, finished papers, ceramicarticles and glass articles, specifically automobiles, parts forautomobiles (for example, body, bumper, spoiler, mirror, wheel such asaluminum wheel and inner package material, and these parts are made ofvarious materials), metal plates such as steel plates, two-wheelbarrows, parts for two-wheel barrows, materials for road (for example,steel rail and traffic control sign), materials for tunnel (for example,sidewall plate), marine vessels, railway vehicles, airplanes, printingmachines, parts for printing machines, furnitures, musical instruments,house-hold electric instruments, building materials, vessels, officearticles, sport articles and toys.

The coating composition of the invention can be utilized in an ink, anadhesive agent and a mold except for the coating composition.

EXAMPLES

The invention is explained in detail with reference to the followingexamples; however, these examples are intended to illustrate theinvention and are not to be construed to limit the scope of theinvention.

Preparation of the test panels and evaluation of the properties of thecured film were conducted as follows.

(1) Preparation of a clear coat test panel

An epoxy resin coating composition for baking (EPICO PRIMER No. 1000BF2, a product of NOF CORPORATION) was applied on a cold-finished steelplate (JIS G-3141) in the amount to form a film having dried thicknessof 20 μm and the steel plate was baked in the condition of 160° C. for20 minutes. And the mixture of an urethane resin coating composition,HIGHURETHANE No. 5000 (white) (a registered trade mark and a product ofNOF CORPORATION) and a curing agent, HIGHURETHANE CURING AGENT HA (aregistered trade mark and a product of NOF CORPORATION) in ratio of 6: 1in parts by weight was applied on the primer coat in the amount to forma film having dried thickness of 25 μm, and the steel plate was dried inforced dried condition of 80° C. for 30 minutes and then was allowed toplace in a night to prepare the test panel.

(2) Preparation of a enamel coat test panel

An epoxy resin coating composition for baking (EPICO PRIMER No. 1000BF2, a product of NOF CORPORATION) was applied on a cold-finished steelplate in the amount to form a film having dried thickness of 20 μm andthe steel plate was baked in the condition of 160° C. for 20 minutes toprepare the test panel.

(3) Evaluation of properties of cured films

(a) 60 degree specular gloss

The 60 degree specular gloss (Gs 60°) of the cured film was measuredaccording to Japanese Industrial Standard K-5400 (1990) 7. 6.

(b) distinctness of image

The distinctness of image of the cured film was evaluated by visualobservation according to the following standard.

∘: When a fluorescent lamp was projected on the cured film, thefluorescent lamp was vividly observed.

Δ: When a fluorescent lamp was projected on the cured film, the outlineof the fluorescent lamp was dimly observed.

X : When a fluorescent lamp was projected on the cured film, thefluorescent lamp was remarkable dimly observed.

(c) accelerated weathering resistance test

By using a weathering resistance tester of sunshine carbon arc lamp(Japanese Industrial Standard D-0205 5.4), a test piece was exposed anda retention of the 60 degree specular gloss (Japanese IndustrialStandard K-5400 (1990) 7.6) of the cured film was measured.

(d) moisture resistance

The test piece was exposed under the condition of 40 ±1° C. and relativehumidity of 95 or more % for 240 hours and then was taken out. Thesurface condition of the test piece was observed by visual after 2 hoursfrom taking out time and was evaluated according to the followingstandard.

∘: The change of the gloss and the surface condition of the test piecewas not observed compared with an original test piece.

Δ: The change of the gloss and blistering of the test piece was observedin small portions compared with an original test piece.

X : The change of the gloss and blistering of the test piece wasremarkably observed compared with an original test piece.

(e) xylene rubbing resistance

On a test piece, a flannel soaked with xylene was rubbed byreciprocating 100 times. The surface condition of the test piece wasobserved by visual and was evaluated in the following standard.

∘: The change of the gloss and the surface condition of the test piecewas not observed compared with an original test piece.

Δ: The change of the gloss of the test piece was observed in smallportions compared with an original test piece.

X : The change of the gloss of the test piece was remarkably observedcompared with an original test piece.

(f) acid resistance

The acid resistance test was conducted according to Japanese IndustrialStandard K-5400 (1990) 8.22 and the acid resistance was evaluated in thefollowing standard.

∘: The change of the gloss and the discoloration of the test piece wasnot observed compared with an original test piece.

Δ: The change of the gloss and the discoloration of the test piece wasobserved in small portions compared with an original test piece.

X : The change of the gloss and the discoloration of the test piece wasremarkably observed compared with an original test piece.

(g) alkali resistance

The alkali resistance test was conducted according to JapaneseIndustrial Standard K-5400 (1990) 8.21 and the alkali resistance wasevaluated in the following standard.

∘: The change of the gloss and the discoloration of the test piece wasnot observed compared with an original test piece.

Δ: The change of the gloss and the discoloration of the test piece wasobserved in small portions compared with an original test piece.

X : The change of the gloss and the discoloration of the test piece wasremarkably observed compared with an original test piece.

(h) oil ink stain resistance

On the test piece, a line of oil ink was drawn and the test piece washeat at 80° C. for 5 hours. And the line of oil ink was wiped with aflannel soaked with xylene. The surface condition of the test piece wasobserved by visual and was evaluated in the following standard.

∘: The line of oil ink was completely wiped and there was not the traceleft behind.

Δ: The trace of the line was observed in small portions.

X : The trace of the line was clearly observed.

(i) pencil hardness

The pencil hardness was measured according to Japanese IndustrialStandard K-5400 (1990) 8.4.2.

(j) adhesive property

By the adhesive property test according to Japanese Industrial StandardK-5400 (1990) 8.5.1, the adhesive property was evaluated in thefollowing standard.

∘: 10 point

Δ: 8 point

X: not more than 6 point

(k) appearance of a thick cured film

The cured film was prepared to form a film having dried thickness of 60μm. The surface condition was observed by visual and evaluated in thefollowing standard.

∘: good

Δ: There were pop marks on a part of the surface of the film.

X: There were pop marks on all surface of the film.

(1) stain property in atmospheric exposure

The atmospheric exposure test of test piece was conducted for 3 monthsand stain property was evaluated by a difference (ΔL) which iscalculated by subtract L value after the atmospheric exposure frominitial L value before the atmospheric exposure, measured by SM colorcomputer SM-4-MCH (a product of SUGA TEST MACHINE CO. LTD.).

(4) workability

(m) atomization

The condition of the atomization at applying was observed and wasevaluated in the following standard.

⊚: very good

∘: good

Δ: bad in a part of atomization

X: bad in overall atomization

(n) transfer efficiency

Transfer efficiency means an transfer efficiency of the atomized coatingcomposition on the substrate. The transfer efficiency was evaluated inthe following standard by observing the extensive state of the coatingcomposition mists and the transfer rate of the mists on the substrate atapplying overall.

⊚: very good

∘: good

Δ: bad in a part of the substrate

X: bad in overall the substrate

(o) stain after removing stains

On the surface of the exposed test piece, a gauze soaked withion-exchange water was rubbed by reciprocating 10 times, and the gauzewas exchanged, and then a new gauze soaked with ion-exchange water wasrubbed by reciprocating 10 times to remove stains. Further, water on thetest piece was wiped up by a dried gauze. Stain property of the curedfilm was evaluated by a difference (ΔL) which is calculated by subtractL value after the atmospheric exposure from initial L value before theatmospheric exposure, measured by the color computer.

Preparation Example 1

Into a reaction vessel equipped with a stirrer, a thermometer, a refluxcondenser and a dropping funnel, 50 parts by weight of xylene and 50parts by weight of isobutyl-acetate were charged and the mixture washeated to keep at the temperature of 110° C.

To the mixture kept at 110° C., a mixture of 61 parts by weight ofmethyl-methacrylate, 19 parts by weight of butyl-acrylate, 19 parts byweight of 2-hydroxyethyl-methacrylate, 1 part by weight of methacrylicacid and 2 parts by weight of 2, 2 ′-azobis (2 -methylbutyronitrile) wasadded by dropping for 2 hours. After the completion of dropping, themixture was kept stirring at 110° C. for 1 hour and a mixture of 0.2parts by weight of 2,2′-azobis (2-methylbutyronitrile) and 2 parts byweight of isobutyl-acetate was added and the mixture was kept stirringfor further 1 hour. After completion of polymerization, a resin solutioncontaining 50.2 percent by weight of non-volatile material was obtained.

The obtained resin had a glass transition temperature of 50° C., anumber average molecular weight of 4,800, a hydroxyl value of 80 mgKOH/gand an acid value of 7 mgKOH/g.

Preparation Examples 2 to 14

By using solvents, monomers and polymerization initiators in kind andthe amount shown in Tables 1 to 4, resin solutions were prepared in thesame method as described in Preparation example 1.

The properties of the obtained resins were shown in Tables 1 to 4.

TABLE 1 Preparation Example 1 2 3 4 initial xylene 50 50 50 50 (parts byisobutyl-acetate 50 50 50 50 weight) dropping methyl-methacrylate 61 7078 80 (parts by butyl-acrylate 19 10 2 — weight) cyclohexyl-metha- — — —— crylate isobornyl-methacrylate — — — — 2-hydroxyethyl-metha- 19 19 1919 crylate FM-2 — — — — methacrylic acid 1 1 1 1 styrene — — — —acrylonitrile — — — — ABMBN 2 2 2 2 additional ABMBN 0.2 0.2 0.2 0.2(parts by isobutyl-acetate 2 2 2 2 weight) total (parts by weight) 204.2204.2 204.2 204.2 non-volatile matter concentration 50.2 50.1 50.0 50.2(weight %) resin glass transition tem- 50 70 90 95 properties perature(° C.) number average 4800 4800 4700 4800 molecular weight hydroxylvalue 80 80 80 80 (mgKOH/g) acid value (mgKOH/g) 7 7 7 7 notes FM-2:ε-caprolactone-modified hydroxymethacrylate (trade name, a product ofDaicel Chemical Industries, Ltd.) ABMBN: 2,2′-azobis(2-methylbutyronitrile)

TABLE 2 Preparation Example 5 6 7 8 initial xylene 50 50 50 50 (parts byisobutyl-acetate 50 50 50 50 weight) dropping methyl-methacrylate 75 6371 67 (parts by butyl-acrylate 12 8 10 11 weight) cyclohexyl-metha- — —— — crylate isobornyl-methacrylate — — — — 2-hydroxyethyl-metha- 12 2818.7 18.9 crylate FM-2 — — — — methacrylic acid 1 1 0.3 3.1 styrene — —— — acrylonitrile — — — — ABMBN 2 2 2 2 additional ABMBN 0.2 0.2 0.2 0.2(parts by isobutyl-acetate 2 2 2 2 weight) total (parts by weight) 204.2204.2 204.2 204.2 non-volatile matter concentration 50.3 50.0 50.2 50.1(weight %) resin glass transition tem- 70 70 70 70 properties perature(° C.) number average 5000 4700 4900 4800 molecular weight hydroxylvalue 50 120 80 80 (mgKOH/g) acid value (mgKOH/g) 7 7 2 20

TABLE 3 Preparation Example 9 10 11 12 initial xylene 50 50 50 50 (partsby isobutyl-acetate 50 50 50 50 weight) dropping methyl-methacrylate 7021 42 — (parts by butyl-acrylate 10 6 6 — weight) cyclohexyl-metha- — 5130 — crylate isobornyl-methacrylate — — — 80 2-hydroxyethyl-metha- 19 2121 19 crylate FM-2 — — — — methacrylic acid 1 1 1 1 styrene — — — —acrylonitrile — — — — ABMBN 1 2 2 2 additional ABMBN 0.2 0.2 0.2 0.2(parts by isobutyl-acetate 2 2 2 2 weight) total (parts by weight) 203.2204.2 204.2 204.2 non-volatile matter concentration 50.2 50.2 50.2 50.1(weight %) resin glass transition tem- 70 70 73 99 properties perature(° C.) number average 12000 4900 5000 4600 molecular weight hydroxylvalue 80 90 90 80 (mgKOH/g) acid value (mgKOH/g) 7 6 6 7

TABLE 4 Preparation example 13 14 initial xylene 50 50 (parts byisobutyl-acetate 50 50 weight) dropping methyl-methacrylate 34 20 (partsby butyl-acrylate — — weight) cyclohexyl-methacrylate 35 15isobornyl-methacrylate — — 2-hydroxyethyl-methacrylate 10 10 FM-2 20 20methacrylic acid 1 1 styrene — 17 acrylonitrile — 17 ABMBN 2 2additional ABMBN 0.2 0.2 (parts by isobutyl-acetate 2 2 weight) total(parts by weight) 204.2 204.2 non-volatile matter concentration (weight%) 50.2 50.2 resin glass transition temperature (° C.) 58 59 propertiesnumber average molecular 5000 4900 weight hydroxyl value (mgKOH/g) 74 74acid value (mgKOH/g) 7 7

Preparation Example 15

Into a reaction vessel equipped with a stirrer, a thermometer, a refluxcondenser having a Dean * Stark trap and a dropping funnel, 1000 partsby weight of SNOWTEX MIBK-ST (a product of Nissan Chemical Industries,Ltd., a dispersing component of silica sol (average particle diameter:30 nm), non-volatile material: 30 percent by weight, solvent:methylisobutylketone) and 40 parts by weight of A-163 (a product ofNippon Unicar Co., Ltd., a silane coupling agent) were charged and themixture was heated and kept at 80 ° C. for 8 hours. The resultant silicasol surface-treated with a silane coupling agent was obtained in 1020parts by weight. The average particle diameter of the dispersingcomponent of silica sol is 32 nm.

Preparation Example 16

By using solvents, monomers and polymerization initiators in kind andamount shown in Tables 5, resin solutions were prepared in the samemethod as described in Preparation Example 1.

The properties of the obtained resins were shown in Tables 5.

TABLE 5 Preparation Example 16 initial xylene 50 (parts by isobutylacetate 50 weight) dropping methylmethacrylate 66 (parts bybutylacrylate 13 weight) 2-hydroxyethylmethacrylate 19trimethoxysilylpropyl-methacrylate 1 methacrylic acid 1 ABMBN 2additional ABMBN 0.2 (parts by isobutyl acetate 2 weight) total (partsby weight) 204.2 non-volatile matter concentration (weight %) 50.2 resinglass transition temperature (° C.) 65 properties number averagemolecular weight 5000 hydroxyl value (mgKOH/g) 80 acid value (mgKOH/g) 7

Example 1

By mixing 45.0 parts by weight of the resin solution obtained inPreparation Example 1, 4.5 parts by weight of cyclohexanone, 41.2 partsby weight of the surface-treated silica sol obtained in PreparationExample 15, 0.8 parts by weight of TINUVIN 900 (a product of Ciba-GeigyCo., an ultraviolet absorber), 0.2 parts by weight of TINUVIN 292 (aproduct of Ciba-Geigy Co., an hinderedamine antioxidant), 1.0 parts byweight of BYK-358 (a product of BYK Chemie, a leveling agent), 1.0 partsby weight of 1 percent by weight solution of SCAT-8 (a product of SankyoOrganic Synthesis Co. Ltd., a tin curing catalyst) and 6.3 parts byweight of DURANATE THA-100 (a product of Asahi Chemical Industry Co.,Ltd., a polymer of hexamethylenediisocyanate) under stirring, a coatingcomposition was prepared.

And, the coating composition was diluted by a solvent mixture ofSOLVESSO #100® (a product of Esso Co.) and cyclohexanone (in ratio byweight: 50: 50) to the viscosity of 15 seconds at 20° C. by Ford cup No.4 and the diluted coating composition was applied on the clear coat testpanel by air spraying (atomization pressure: 5 kg/cm²) in the amount toform a film having dried thickness of 30 μm. The coated clear coat testpanel was dried by forced drying at 80° C. for 30 minutes. After beingplaced for 3 days at room temperature, the cured film properties wereevaluated.

The compounding rates of each ingredients in the coating composition andbaking conditions were shown in Table 6 and the cured film propertieswere shown in Table 9.

Examples 2 through 15

After coating compositions were prepared in compounding rate shown inTables 6 to 8 in the same method as described in Example 1, cured filmswere formed on test panels. Baking conditions and forced dryingconditions at forming cured films were shown in Tables 6 to 8 and thecured film properties were shown in Tables 9 to 11.

Example 16

By mixing and dispersing 52.5 parts by weight of titanium oxide (DUPONTTITANIUM R-960, a product of Dupont Co.), 35.0 parts by weight of theresin solution obtained in Preparation Example 1 and 12.5 parts byweight of cyclohexanone in a motor mill (a product of Eiger Japan Co. )at 3,000 rpm for 40 minutes, a pigment-dispersed coating compositionsolution was prepared.

And, 46.9 parts by weight of the pigment-dispersed coating compositionsolution, 22.0 parts by weight of the resin solution obtained inPreparation Example 1, 3.0 parts by weight of cyclohexanone, 20.5 partsby weight of the surface-treated silica sol obtained in PreparationExample 15, 0.2 parts by weight of TINUVIN 292, 1.0 parts by weight ofBYK-358, 1.0 parts by weight of 1 percent by weight solution of SCAT-8and 5.4 parts by weight of DURANATE THA-100 were mixed under stirringand a coating composition was prepared.

Further, the coating composition was diluted by a solvent mixture ofSOLVESSO #100® (a product of Esso Co.) and cyclohexanone (in ratio byweight : 50 : 50) to the viscosity of 15 seconds at 20° C. by Ford cupNo. 4 and the diluted coating composition was applied on the test panelby air spraying (atomization pressure: 5 kg/cm²) in the amount to form afilm having dried thickness of 30 μm. The test panel was dried by forceddrying at 80° C. for 30 minutes. Furthermore, after being placed for 3days at room temperature, the cured film properties were evaluated.

The cured film properties were shown in Table 12.

TABLE 6 Example 1 2 3 4 5 compounding resin kind (Preparation Prep. Ex.Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate solution Example) 1 2 3 4 5(parts by formulation weight 45.0 45.0 49.6 46.9 45.8 weight) silica soluntreated silica sol — 41.2 — — — Preparation Ex. 15 41.2 — 29.0 15.740.9 curing DURANATE THA-100 6.3 6.3 — — 5.7 agent DURANATE 24A-100 — —— 9.9 — DISMODUR BL-3175 — — 13.4 — — solvent cyclohexanone 4.5 4.5 5.06.5 4.6 additive TINUVIN 900 0.8 0.8 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.20.2 0.2 BYK-358 1.0 1.0 1.0 1.0 1.0 curing SCAT-8 (10% by — — 1.0 — —catalyst weight solution) SCAT-8 (1% by 1.0 1.0 — 1.0 1.0 weightsolution) total 100.0 100.0 100.0 100.0 100.0 NCO/OH (mole ratio) 1.01.0 1.0 1.0 1.4 silica sol non-volatile matter/total non- 30.0 30.0 20.010.0 30.0 volatile matter (percent by weight) baking or forced dryingtemperature (° C.) 80 80 150 80 80 condition time (minutes) 30 30 20 3030 notes DURANATE 24A-100: a product of Asahi Chemical Industries Co.Ltd., a polymer of hexamthylenediisocyanate

DESMODUR BL-3175: a product of Sumitomo Bayer Urethane Co. Ltd., apolymer of blocked type hexamthylenediisocyanate

TABLE 7 Example 6 7 8 9 10 compounding resin kind (Preparation Prep. Ex.Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate solution Example) 6 7 8 910 (parts by formulation weight 52.0 54.6 54.6 69.8 47.2 weight) silicasol untreated silica sol — — — — — Preparation Ex. 15 29.9 29.2 29.214.9 29.5 curing DURANATE THA-100 — 7.7 7.7 — — agent DURANATE 24A-1009.9 — — 5.3 — DISMODUR BL-3175 — — — — 15.7 solvent cyclohexanone 5.25.5 5.5 7.0 4.7 additive TINUVIN 900 0.8 0.8 0.8 0.8 0.8 TINUVIN 292 0.20.2 0.2 0.2 0.1 BYK-358 1.0 1.0 1.0 1.0 1.0 curing SCAT-8 (10% by — — —— 1.0 catalyst weight solution) SCAT-8 (1% by 1.0 1.0 1.0 1.0 — weightsolution) total 100.0 100.0 100.0 100.0 100.0 NCO/OH (mole ratio) 0.81.0 1.0 0.6 1.1 silica sol non-volatile matter/total non- 20.0 20.0 20.010.0 20.0 volatile matter (percent by weight) baking or forced dryingtemperature (° C.) 80 80 80 80 150 condition time (minutes) 30 30 30 3020

TABLE 8 Example 11 12 13 14 15 compounding resin kind (Preparation Prep.Ex. Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate solution Example) 11 1213 14 11 (parts by formulation weight 53.6 62.0 36.4 21.8 53.6 weight)silica sol untreated silica sol — — — — — Preparation Ex. 15 29.5 16.251.9 69.9 29.5 curing DURANATE THA-100 8.5 — — — — agent DURANATE24A-100 — 12.6 5.1 3.1 — DISMODUR BL-3175 — — — — — solventcyclohexanone 5.4 6.2 3.6 2.2 6.4 additive TINUVIN 900 0.8 0.8 0.8 0.80.8 TINUVIN 292 0.2 0.2 0.2 0.2 0.2 BYK-358 1.0 1.0 1.0 1.0 1.0 curingSCAT-8 (10% by — — — — — catalyst weight solution) SCAT-8 (1% by 1.0 1.01.0 1.0 — weight solution) total 100.0 100.0 100.0 100.0 100.0 NCO/OH(mole ratio) 1.1 1.6 1.2 1.2 1.1 silica sol non-volatile matter/totalnon- 20.0 10.0 40.0 60.0 20.0 volatile matter (percent by weight) bakingor forced drying temperature (° C.) 80 80 80 80 120 condition time(minutes) 30 30 30 30 30

TABLE 9 Example 1 2 3 4 5 operation efficiency atomization ∘ ∘ ∘ ∘ ∘ incoating process transfer efficiency ∘ ∘ ∘ ∘ ∘ cured 60° gloss 93 91 9186 92 film distinctness of image ∘ ∘ ∘ ∘ ∘ properties accelerated 1000hours 100 100 100 99 100 weathering test 2000 hours 99 97 99 99 98 glossretention (%) 3000 hours 95 95 96 97 95 4000 hours 92 93 93 96 90 5000hours 91 92 91 93 87 6000 hours 90 92 91 92 85 moisture resistance ∘ ∘ ∘∘ ∘ xylene rubbing resistance ∘ ∘ ∘ ∘ ∘ acid resistance ∘ ∘ ∘ ∘ ∘ alkaliresistance ∘ ∘ ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ ∘ ∘ resistance red ∘ ∘ ∘∘ ∘ pencil hardness (breaking) 3H 3H 4H 4H 3H pencil hardness (cloud) FH H˜2H H H adhesive property ∘ ∘ ∘ ∘ ∘ appearance of a thick coated Δ ΔΔ Δ Δ stain property in atomospheric 0.8 3.0 1.0 1.5 0.7 exposure (ΔL)stain after removing stains (ΔL) 0.1 0.2 0.1 0.2 0.3

TABLE 10 Example 6 7 8 9 10 operation efficiency atomization ∘ ∘ ∘ ∘ ∘in coating process transfer efficiency ∘ ∘ ∘ ∘ ∘ cured 60° gloss 91 9388 90 91 film distinctness of image ∘ ∘ ∘ ∘ ∘ properties accelerated1000 hours 100 100 98 100 99 weathering test 2000 hours 98 98 97 98 97gloss retention (%) 3000 hours 95 95 94 96 93 4000 hours 91 93 90 94 935000 hours 90 91 87 93 92 6000 hours 90 88 84 93 90 moisture resistance∘ ∘ ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ ∘ ∘ acid resistance ∘ ∘ ∘ ∘ ∘alkali resistance ∘ ∘ ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ ∘ ∘ resistance red∘ ∘ ∘ ∘ ∘ pencil hardness (breaking) 4H 4H 4H 4H 4H pencil hardness(cloud) 2H H H H 2H adhesive property ∘ ∘ ∘ ∘ ∘ appearance of a thickcoated Δ Δ Δ Δ Δ stain property in atomospheric 1.0 1.1 1.1 1.6 1.0exposure (ΔL) stain after removing stains (ΔL) 0.1 0.2 0.2 0.1 0.3

TABLE 11 Example 11 12 13 14 15 operation efficiency atomization ∘ ∘ ∘ ∘∘ in coating process transfer efficiency ∘ ∘ ∘ ∘ ∘ cured 60° gloss 91 8594 94 91 film distinctness of image ∘ ∘ ∘ ∘ ∘ properties accelerated1000 hours 99 99 99 99 99 weathering test 2000 hours 99 98 97 94 99gloss retention (%) 3000 hours 98 98 93 90 98 4000 hours 96 95 90 87 965000 hours 95 94 84 92 95 6000 hours 93 91 82 79 93 moisture resistance∘ ∘ ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ ∘ ∘ acid resistance ∘ ∘ ∘ ∘ ∘alkali resistance ∘ ∘ ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ ∘ ∘ resistance red∘ ∘ ∘ ∘ ∘ pencil hardness (breaking) 4H 4H 2H 3H 4H pencil hardness(cloud) H H˜2H H H H adhesive property ∘ ∘ ∘ ∘ ∘ appearance of a thickcoated Δ Δ Δ Δ Δ stain property in atomospheric 1.1 1.6 0.5 0.4 0.9exposure (ΔL) stain after removing stains (ΔL) 0.2 0.2 0.2 0.2 0.2

TABLE 12 Example 16 operation efficiency atomization ◯ in coatingprocess transfer efficiency ◯ cured 60° gloss 90 film distinctness ofimage ◯ properties accelerated 1000 hours 100 weathering test 2000 hours99 gloss retention (%) 3000 hours 95 4000 hours 92 5000 hours 87 6000hours 85 moisture resistance ◯ xylene rubbing resistance ◯ acidresistance ◯ alkali resistance ◯ oil ink stain black ◯ resistance red ◯pencil hardness (breaking) 4 H pencil hardness (cloud) 2 H adhesiveproperty ◯ appearance of a thick coated Δ stain property in atomospheric1.0 exposure (ΔL) stain after removing stains (Δ 0.1 L)

Reference Example 1 through 3

By using solvents, monomers and polymerization initiators in kind andamount shown in Table 13, resin solutions were prepared in the samemethod as described in Preparation Example 1.

The properties of the obtained resins were shown in Table 13.

TABLE 13 Reference Example 1 2 3 initial xylene 50 50 50 (parts byisobutyl acetate 50 50 50 weight) dropping methylmethacrylate 50 67.263.6 (parts by butylacrylate 30 27.7 2.5 weight) 2-hydroxylethylmethacrylate 19 4.6 — 2-hydroxylethyl acrylate — — 33.1 methacrylic acid1 0.5 0.8 ABMBN 2 2 2 additional ABMBN 0.2 0.2 0.2 (parts by isobutylacetate 2 2 2 weight) total (parts by weight) 204.2 204.2 204.2non-volatile matter conc. (percent by weight) 50.2 50.1 50.2 resin glasstransition temperature 30 40 50 properties (° C.) number averagemolecular 4900 4900 4800 weight hydroxyl value (mgKOH/g) 80 20 160 acidvalue (mgKOH/g) 7 3 5

Comparative Example 1

By mixing 49.6 parts by weight of the resin solution obtained inReference Example 1, 5.0 parts by weight of cyclohexanone, 29.0 parts byweight of the surface-treated silica sol obtained in Preparation Example15, 0.8 parts by weight of TINUVIN 900 (described above), 0.2 parts byweight of TINUVIN 292 (described above), 1.0 parts by weight of BYK-358,1.0 parts by weight of 10 percent by weight solution of SCAT-8 and 13.4parts by weight of DESMODUR BL-3175 under stirring, a coatingcomposition was prepared.

And, the coating composition was diluted by a solvent mixture ofSOLVESSO #100® (a product of Esso Co.) and cyclohexanone (in ratio byweight: 50: 50) to the viscosity of 15 seconds at 20° C. by Ford cup No.4 and the diluted coating composition was applied on the clear coat testpanel by air spraying (atomization pressure: 5 kg/cm²) in the amount toform a film having dried thickness of 30 μm. The coated clear coat testpanel was baked at 140° C. for 30 minutes. Further, after being placedfor 3 days at room temperature, the cured film properties wereevaluated.

The compounding rates of each ingredients in the coating composition,baking conditions and forced drying condition were shown in Table 14 andthe cured film properties were shown in Table 16.

Comparative Examples 2 through 7

After coating compositions were prepared in compounding rate shown inTable 14 in the same method as described in Comparative Example 1, curedfilms were formed on test panels. Baking conditions and forced dryingconditions at forming cured films were shown in Table 15 and the curedfilm properties were shown in Table 17.

TABLE 14 Comparative Example 1 2 3 4 5 compounding resin kind (ReferenceRef. Ex. Ref. Ex. Ref. Ex. Ref. Ex. Ref. Ex. rate solution Example) 1 23 4 5 (parts by formulation weight 49.6 72.3 60.6 74.4 18.9 weight)silica sol untreated silica sol — — 16.4 — — Preparation Ex. 15 29.014.5 — 4.8 73.4 curing DURANATE THA-100 — 3.0 — — 2.5 agent DURANATE24A-100 — — 13.9 10.4 — DISMODUR BL-3175 13.4 — — — — solventcyclohexanone 5.0 7.2 6.1 7.4 1.9 additive TINUVIN 900 0.8 0.8 0.8 0.80.8 TINUVIN 292 0.2 0.2 0.2 0.2 0.2 BYK-358 1.0 1.0 1.0 1.0 1.0 curingSCAT-8 (10% by 1.0 — — — — catalyst weight solution) SCAT-8 (1% by — 1.01.0 1.0 1.0 weight solution) total 100.0 100.0 100.0 100.0 100.0 NCO/OH(mole ratio) 1.0 1.2 0.9 1.1 1.0 silica sol non-volatile matter/totalnon- 20.0 10.0 10.0 2.9 64.9 volatile matter (percent by weight) bakingor forced drying temperature (° C.) 150 80 80 80 80 condition time(minutes) 20 30 30 30 30

TABLE 15 Comparative Example 6 7 compounding resin kind (PreparationAROTAN AROTAN rate solution Example) UW2818 UW2818 (parts by formulationweight 100 100 weight) organo silica sol 50 — organo titania sol — 50curing DURANATE THA- — — agent 100 DURANATE 24A- — — 100 DISMODUR BL- —— 3175 CORONATE 2515 35.8 35.8 solvent cyclohexanone — — additiveTINUVIN 900 — — TINUVIN 292 — — BYK-358 — — curing SCAT-8 (10% by — —catalyst weight solution) SCAT-8 (1% by — — weight solution) total 185.8185.8 NCO/OH (mole ratio) — — silica sol non-volatile matter/total non-10.8 — volatile matter (percent by weight) baking or forced dryingtemperature (° C.) 160 160 condition time (minutes) 20 20

AROTAN UW2818: a product of Nippon Shokubai Co., Ltd., an acrylic polyolresin, non-volatile material 60 percent by weight CORONATE 2515: aproduct of Nippon Polyurethane Kogyo Co., Ltd., isocyanate, non-volatilematerial 80 percent by weight organo silica sol: non-volatile material30 percent by weight organo titania sol: non-volatile material 30percent by weight

TABLE 16 Comparative Example 1 2 3 4 5 operation efficiency atomization∘ ∘ ∘ Δ ∘ in coating process transfer efficiency ∘ ∘ ∘ ∘ ∘ cured 60°gloss 92 92 91 93 85 film distinctness of image ∘ ∘ ∘ ∘ x propertiesaccelerated 1000 hours 98 97 91 98 90 weathering test 2000 hours 90 9175 91 81 gloss retention (%) 3000 hours 84 80 53* 77 50* 4000 hours 7168 42 68 38 5000 hours 60 53 30 60 22 6000 hours 49 39 15 51 12 moistureresistance ∘ ∘ ∘ ∘ Δ xylene rubbing resistance ∘ x ∘ ∘ ∘ acid resistance∘ ∘ ∘ ∘ ∘ alkali resistance ∘ ∘ ∘ ∘ Δ oil ink stain black Δ Δ ∘ Δ ∘resistance red x x Δ Δ Δ pencil hardness (breaking) 2H 2H 3H 3H 4Hpencil hardness (cloud) HB HB F F 2H adhesive property ∘ ∘ ∘ ∘ Δappearance of a thick coated Δ Δ Δ Δ Δ stain property in atomospheric1.1 1.5 1.5 5.0 0.5 exposure (ΔL) stain after removing stains (ΔL) 1.01.4 1.3 2.0 0.1 *Cracks exist.

TABLE 17 Comparative Example 6 7 operation efficiency atomization Δ Δ incoating process transfer efficiency X X cured 60° gloss 91 90 filmdistinctness of image ◯ ◯ properties accelerated 1000 hours 97 91weathering test 2000 hours 80 78 gloss retention (%) 3000 hours 71 574000 hours 50 48 5000 hours 27 35 6000 hours 15 21 moisture resistance ◯◯ xylene rubbing resistance ◯ ◯ acid resistance ◯ ◯ alkali resistance ◯◯ oil ink stain black Δ Δ resistance red X X pencil hardness (breaking)4 H 2 H pencil hardness (cloud) H H B adhesive property ◯ ◯ appearanceof a thick coated X X stain property in atomospheric 6.0 7.5 exposure(ΔL) stain after removing stains (Δ 3.8 5.9 L)

Example 17

By mixing 45.0 parts by weight of the resin solution obtained inPreparation Example 1,4.5 parts by weight of cyclohexanone, 41.2 partsby weight of the surface-treated silica sol obtained in PreparationExample 15, 0.8 parts by weight of TINUVIN 900 (a product of Ciba-GeigyCo., an ultraviolet absorber), 0.2 parts by weight of TINUVIN 292 (aproduct of Ciba-Geigy Co., a hindered amine antioxidant), 1.0 parts byweight of BYK-358 (a product of Bickemy Co., a leveling agent), 7.3parts by weight of UVAN 220 (a product of Mitsui Toatsu Chemicals, Inc.a melamine resin) under stirring, a coating composition was prepared.

And, the coating composition was diluted by a solvent mixture ofSOLVESSO #100® (a product of Esso Co.) and cyclohexanone (in ratio byweight: 50 : 50) to the viscosity of 15 seconds at 20° C. by Ford cupNo. 4 and the diluted coating composition was applied on the clear coattest panel by air spraying (atomization pressure: 5 kg/cm²) in theamount to form a film having dried thickness of 30 μm. The coated clearcoat test panel was baked at 140° C. for 30 minutes. Furthermore, afterbeing placed it for 3 days at room temperature, the cured filmproperties were evaluated.

The compounding rates of each ingredients in the coating composition,baking condition and forced drying condition were shown in Table 18 andthe cured film properties were shown in Table 21.

Examples 18 through 30, and 32

After coating compositions were prepared in compounding rate shown inTables 18 to 20 in the same method as described in Example 17, curedfilms were formed on test panels. Baking conditions and forced dryingconditions at forming cured films were shown in Tables 18 to 20 and thecured film properties were shown in Tables 21 to 23.

Example 31

By mixing and dispersing 52.5 parts by weight of titanium oxide (DUPONTTITANIUM R-960, a product of Dupont Co.), 35.0 parts by weight of theresin solution obtained in Preparation Example 1 and 12.5 parts byweight of cyclohexanone in a motor mill (a product of Eiger Japan Co. )at 3,000 rpm for 40 minutes, a pigment-dispersed coating composition wasprepared.

And, 46.9 parts by weight of the pigment-dispersed coating composition,22.0 parts by weight of the resin solution obtained in PreparationExample 1, 3.0 parts by weight of cyclohexanone, 20.5 parts by weight ofthe surface-treated silica sol obtained in Preparation Example 15, 0.2parts by weight of TINUVIN 292, 1.0 parts by weight of BYK-358, 6.4parts by weight of UVAN 220 (a product of Mitsui Toatsu Chemicals, Inc.a melamine resin) were mixed under stirring and a coating compositionwas prepared.

Further, the coating composition was diluted by a solvent mixture ofSOLVESSO #100® (a product of Esso Co.) and cyclohexanone (in ratio byweight: 50: 50) to the viscosity of 15 seconds at 20° C. by Ford cup No.4 and the diluted coating composition was applied on the test panel byair spraying (atomization pressure: 5 kg/cm²) in the amount to form afilm having dried thickness of 30 μm. The test panel was baked at 140°C. for 30 minutes. Furthermore, after being placed for 3 days at roomtemperature, the cured film properties were evaluated.

The cured film properties were shown in Table 23.

TABLE 18 Example 17 18 19 20 21 compounding resin kind (PreparationPrep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate solution Example)1 2 3 4 5 (parts by formulation weight 45.0 45.0 50.0 80.0 45.0 weight)silica sol untreated silica sol — 35.9 — — — Preparation Ex. 15 35.9 —33.0 5.0 40.9 curing UVAN 220 12.6 12.6 — — 7.4 agent UVAN 122 — — — 6.5— CYMEL 370 — — 10.0 — — solvent cyclohexanone 4.5 4.5 5.0 6.5 4.6additive TINUVIN 900 0.8 0.8 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.2 0.2 0.2BYK-358 1.0 1.0 1.0 1.0 1.0 curing Nacure 4054 — — — — 0.1 catalysttotal 100.0 100.0 100.0 100.0 100.0 acryl/melamine (weight ratio ofnon-volatile 75/25 75/25 76/24 91/9 84/16 matter) silica solnon-volatile matter/total non- 26.3 26.3 20.0 10.0 31.2 volatile matter(percent by weight) baking or forced drying temperature (° C.) 140 140140 130 140 condition time (minutes) 30 30 20 30 30 notes UVAN 220: aproduct of Mitsui Toatsu Chemicals, Inc. a melamine resin (non-volatilematerial 60 percent by weight) UVAN 122: a product of Mitsui ToatsuChemicals, Inc. a melamine resin (non-volatile material 60 percent byweight) CYMEL 370: a product of Mitsui Cytec Co., Ltd., a melamine resin(non-volatile material 80 percent by weight) Nacure 4054: a products ofKing Industry Co., Ltd., phosphoric acid type curing catalyst

TABLE 19 Example 22 23 24 25 26 compounding resin kind (PreparationPrep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate solution Example)6 7 8 9 10 (parts by formulation weight 52.0 54.6 54.6 70.0 50.0 weight)silica sol untreated silica sol — — — — — Preparation Ex. 15 32.0 27.827.8 15.0 30.0 curing UVAN 220 — — — — — agent UVAN 122 8.7 — — 6.0 —CYMEL 370 — 10.0 10.0 — 13.3 solvent cyclohexanone 5.2 5.5 5.5 7.0 4.7additive TINUVIN 900 0.8 0.8 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.2 0.2 0.2BYK-358 1.0 1.0 1.0 1.0 1.0 curing Nacure 4054 0.1 0.1 0.1 — — catalysttotal 100.0 100.0 100.0 100.0 100.0 acryl/melamine (weight ratio ofnon-volatile 83/17 77/23 77/23 91/9 70/30 matter) silica solnon-volatile matter/total non- 23.5 19.1 19.1 10.4 20.1 volatile matter(percent by weight) baking or forced drying temperature (° C.) 140 130120 140 140 condition time (minutes) 30 30 30 30 30

TABLE 20 Example 27 28 29 30 32 compounding resin kind (PreparationPrep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate solution Example)11 12 13 14 16 (parts by formulation weight 53.6 63.0 36.4 23.7 45.0weight) silica sol untreated silica sol — — — — — Preparation Ex. 1529.5 16.2 52.9 68.0 35.9 curing UVAN 220 9.5 — — — 12.6 agent UVAN 122 —12.6 5.1 4.1 — CYMEL 370 — — — — — solvent cyclohexanone 5.4 6.2 3.6 2.24.5 additive TINUVIN 900 0.8 0.8 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.2 0.20.2 BYK-358 1.0 1.0 1.0 1.0 1.0 curing Nacure 4054 — — — — — catalysttotal 100.0 100.0 100.0 100.0 100.0 acryl/melamine (weight ratio ofnon-volatile 83/17 81/19 86/14 83/17 75/25 matter) silica solnon-volatile matter/total non- 21.3 11.0 42.7 58.7 26.3 volatile matter(percent by weight) baking or forced drying temperature (° C.) 140 140130 130 140 condition time (minutes) 30 30 30 30 30

TABLE 21 Example 17 18 19 20 21 operation efficiency atomization ∘ ∘ ∘ ∘∘ in coating process transfer efficiency ∘ ∘ ∘ ∘ ∘ cured 60° gloss 92 9291 94 93 film distinctness of image ∘ ∘ ∘ ∘ ∘ properties accelerated1000 hours 100 99 98 99 100 weathering test 2000 hours 98 99 97 98 98gloss retention (%) 3000 hours 95 97 94 95 95 4000 hours 92 96 90 93 905000 hours 90 93 87 91 87 6000 hours 88 90 83 86 81 moisture resistance∘ ∘ ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ ∘ ∘ acid resistance ∘ ∘ ∘ ∘ ∘alkali resistance ∘ ∘ ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ ∘ ∘ resistance red∘ ∘ ∘ ∘ ∘ pencil hardness (breaking) 3H 3H 3H 3H 3H pencil hardness(cloud) H H H H H adhesive property ∘ ∘ ∘ ∘ ∘ appearance of a thickcoated Δ Δ Δ Δ Δ stain property in atomospheric 0.9 0.8 1.2 1.5 0.6exposure (ΔL) stain after removing stains (ΔL) 0.3 0.3 0.4 0.5 0.2

TABLE 22 Example 22 23 24 25 26 operation efficiency atomization ∘ ∘ ∘ ∘∘ in coating process transfer efficiency ∘ ∘ ∘ ∘ ∘ cured 60° gloss 91 9590 91 92 film distinctness of image ∘ ∘ ∘ ∘ ∘ properties accelerated1000 hours 99 100 99 100 100 weathering test 2000 hours 98 98 97 99 97gloss retention (%) 3000 hours 96 96 93 94 95 4000 hours 93 94 93 92 935000 hours 91 93 89 89 90 6000 hours 88 91 87 86 87 moisture resistance∘ ∘ ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ ∘ ∘ acid resistance ∘ ∘ ∘ ∘ ∘alkali resistance ∘ ∘ ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ ∘ ∘ resistance red∘ ∘ ∘ ∘ ∘ pencil hardness (breaking) 2H 2H 2H 3H 3H pencil hardness(cloud) F H H H H adhesive property ∘ ∘ ∘ ∘ ∘ appearance of a thickcoated Δ Δ Δ Δ Δ stain property in atomospheric 1.1 1.2 1.3 1.7 1.0exposure (ΔL) stain after removing stains (ΔL) 0.5 0.6 0.6 0.4 0.2

TABLE 23 Example 27 28 29 30 31 32 operation efficiency atomization ∘ ∘∘ ∘ ∘ ∘ in coating process transfer efficiency ∘ ∘ ∘ ∘ ∘ ∘ cured 60°gloss 91 90 86 90 89 89 film distinctness of image ∘ ∘ ∘ ∘ ∘ ∘properties accelerated 1000 hours 99 100 99 99 99 100 weathering test2000 hours 96 99 99 98 97 98 gloss retention (%) 3000 hours 90 95 98 9893 95 4000 hours 87 92 96 95 90 92 5000 hours 82 88 95 93 83 90 6000hours 77 84 89 91 80 88 moisture resistance ∘ ∘ ∘ ∘ ∘ ∘ xylene rubbingresistance ∘ ∘ ∘ ∘ ∘ ∘ acid resistance ∘ ∘ ∘ ∘ ∘ ∘ alkali resistance ∘ ∘∘ ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ ∘ ∘ ∘ resistance red ∘ ∘ ∘ ∘ ∘ ∘pencil hardness (breaking) 3H 3H 3H 3H 4H 4H pencil hardness (cloud) H H2H 2H 2H 2H adhesive property ∘ ∘ ∘ ∘ ∘ ∘ appearance of a thick coated ΔΔ Δ Δ Δ Δ stain property in atomospheric 1.2 1.8 0.3 0.3 0.9 0.9exposure (ΔL) stain after removing stains (ΔL) 0.2 0.3 0.0 0.1 0.2 0.2

Comparative Example 8

By mixing 49.6 parts by weight of the resin solution obtained inReference Example 1, 5.0 parts by weight of cyclohexanone, 29.0 parts byweight of the surface-treated silica sol obtained in Preparation Example15, 0.8 parts by weight of TINUVIN 900 (described above), 0.2 parts byweight of TINUVIN 292, 1.0 parts by weight of BYK-358 and 14.4 parts byweight of UVAN 220 (described above) under stirring, a coatingcomposition was prepared.

And, the coating composition was diluted by a solvent mixture ofSOLVESSO #100® (a product of Esso Co.) and cyclohexanone (in ratio byweight: 50: 50) to the viscosity of 15 seconds at 20° C. by Ford cup No.4 and the diluted coating composition was applied on the clear coat testpanel by air spraying (atomization pressure: 5 kg/cm²) in the amount toform a film having dried thickness of 30 μm. The coated clear coat testpanel was baked at 140° C. for 30 minutes. Further, after being placedfor 3 days at room temperature, the cured film properties wereevaluated.

The compounding rates of each ingredients in the coating composition,baking conditions and forced drying condition were shown in Table 24 andthe cured film properties were shown in Table 25.

Comparative Examples 9 through 12

After coating compositions were prepared in compounding rate shown inTable 24 in the same method as described in Comparative Example 1, curedfilms were formed on test panels. Baking conditions and forced dryingconditions at forming cured films were shown in Table 24 and the curedfilm properties were shown in Table 25.

TABLE 24 Comparative Example 8 9 10 11 12 compounding resin kind(Reference Ref. Ex. Ref. Ex. Ref. Ex. Ref. Ex. Ref. Ex. rate solutionExample) 1 2 3 4 13 (parts by formulation weight 50.9 72.3 61.0 77.520.0 weight) silica sol untreated silica sol — — 16.9 — — PreparationEx. 15 29.0 14.5 — 0.5 73.7 curing UVAN 220 — 3.9 — — 2.6 agent UVAN 122— — 14.0 12.6 — CYMEL 370 13.0 — — — — solvent cyclohexanone 5.0 7.2 6.17.4 1.7 additive TINUVIN 900 0.8 0.8 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.20.2 0.2 BYK-358 1.0 1.0 1.0 1.0 1.0 curing Nacure 4054 0.1 0.1 — — —catalyst total 100.0 100.0 100.0 100.0 100.0 acryl/melamine (weightratio of non-volatile 71/29 94/6 78/22 84/16 87/13 matter) silica solnon-volatile matter/total non- 19.5 10.1 11.5 0.6 65.6 volatile matter(percent by weight) baking or forced drying temperature (° C.) 140 140140 130 140 condition time (minutes) 30 30 30 30 30

TABLE 25 Comparative Example 8 9 10 11 12 operation efficiencyatomization ∘ ∘ ∘ Δ ∘ in coating process transfer efficiency ∘ ∘ ∘ ∘ ∘cured 60° gloss 92 92 91 93 85 film distinctness of image ∘ ∘ ∘ ∘ xproperties accelerated 1000 hours 98 97 91 98 91 weathering test 2000hours 90 91 75 91 82 gloss retention (%) 3000 hours 84 80 53* 75 50*4000 hours 71 68 42 69 36 5000 hours 60 53 30 59 25 6000 hours 49 39 1553 10 moisture resistance ∘ ∘ ∘ ∘ Δ xylene rubbing resistance ∘ x ∘ ∘ ∘acid resistance ∘ ∘ ∘ ∘ ∘ alkali resistance ∘ ∘ ∘ ∘ Δ oil ink stainblack Δ Δ ∘ x ∘ resistance red x x Δ x Δ pencil hardness (breaking) 2H2H 3H 3H 4H pencil hardness (cloud) HB HB F F 2H adhesive property ∘ ∘ ∘∘ Δ appearance of a thick coated Δ Δ Δ Δ Δ stain property inatomospheric 2.9 4.1 4.0 8.0 0.5 exposure (ΔL) stain after removingstains (ΔL) 1.5 1.9 2.0 7.5 0.2 note *generation of cracks

Preparation Example 17

Into a reaction vessel equipped with a stirrer, a thermometer, a refluxcondenser having a Dien Stark trap, a dropping funnel and adecompression device, 180.2 parts by weight of SNOWTEX-O (a trade name,a product of Nissan Chemical Industries Co. Ltd., a water-baseddispersing silica sol, average particle diameter : 20 nm) and 63.1 partsby weight of isopropyl alcohol were charged and the mixture was heatedunder reduced pressure of 150 to 170 mmHg to 42° C. And then dehydrationby azeotropic distillation was carried out with continuously dropping of1216.2 parts by weight of isopropyl alcohol for 10 hours and 234.2 partsby weight of silca sol dispersed in isopropyl alcohol was obtained.Water content of the silca sol dispersed in isopropyl alcohol was 0.8percent by weight as determined by Karl Fischer's moisture titrationmethod. Further, 9 parts by weight of methyltrimethoxysilane was addedinto the silca sol dispersed in isopropyl alcohol and reacted underatmospheric pressure at 40° C. for 24 hours. And isopropyl alcohol wasremoved from the silca sol dispersed in isopropyl alcohol by reducing atreduced pressure of 150 to 170 mmHg with dropping 360.4 parts by weightof cyclohexanone. Then, a part of cyclohexanone was removed from thesilca sol dispersed in cyclohexanone at inner temperature of 50 to 55°C. and 100 parts by weight of the silca sol dispersed in light yellowand transparent cyclohexanone (average particle diameter: 30 nm) wasobtained. The non-volatile material of the obtained silca sol dispersedin cyclohexanone was 45 percent by weight and water content was 0.1percent by weight.

Preparation Examples 18 through 20

By using ingredients in the amount shown in Table 26, dispersingcomponents of silica sol were obtained in the same method as describedin Preparation Example 17. The average particle diameter of dispersingcomponents of silica sol of Preparation Example 18, 19 and 20 were each28 nm, 31 nm and 28 nm.

TABLE 26 Preparation Example 17 18 19 20 water-based silica sol SNOWTEXO 180.2 — — 180.2 SNOWTEX N — 180.2 180.2 — initial solvent isopropylalcohol 63.1 63.1 — — n-propyl alcohol — — 63.1 — isopropylalcohol/n-propyl alcohol = 75/ — — — 63.1 25 continuous dropping solventisopropyl alcohol 1216.2 1373.0 — — n-propyl alcohol — — 436.1 —isopropyl alcohol/n-propyl alcohol = 75/ — — — 818.4 25 weight in middlestage (parts by weight) 234.2 — — — water content in middle stage 0.8(parts by weight) silane coupling agent mthyltrimethoxysilane 9.0 — 4.5— γ-glycidoxypropyltrimethoxysilane — 7.9 — —γ-methacryloiloxypropyltrimethoxy- — — — 12.4 silane solvent in secondstage cyclohexanone 360.4 — — — isophorone — 95.0 — —methylisobutylketone — — 120.0 — butyrosersolv — — — 90.0 yield (partsby weight) 100.0 100.0 100.0 100.0 non-volatile material (% by weight)45.0 45.0 45.0 45.0 water content (% by weight) 0.1 0.1 0.1 0.2

Preparation Example 21

Into a reaction vessel equipped with a stirrer, a thermometer, a refluxcondenser and a dropping funnel, 33.3 parts by weight of xylene and 33.3parts by weight of isobutyl-acetate were charged and the mixture washeated to keep at the temperature of 110° C.

To the mixture kept at 110° C., a mixture of 61 parts by weight ofmethyl-methacrylate, 19 parts by weight of butyl-acrylate, 19 parts byweight of 2-hydroxyethyl-methacrylate, 1 part by weight of methacrylicacid and 1.7 parts by weight of 2,2 ′-azobis (2 -methylbutyronitrile)was added by dropping for 2 hours. After the completion of dropping, themixture was kept stirring at 110° C. for 1 hour. and a mixture of 0.2parts by weight of 2,2′-azobis (2 -methylbutyronitrile) and 2 parts byweight of isobutyl-acetate was added and the mixture was kept stirringfor further 1 hour. After completion of polymerization, 36.9 parts byweight of the dispersing component of silca sol dispersed incyclohexanone obtained in Prep. Ex. 17 was dropped by a dropping funnelfor 10 minutes and then the mixture was kept stirring for further 30minutes. The resultant organic-inorganic composite solution containing57 parts by weight of non-volatile material was obtained. The obtainedorganic-inorganic composite had a glass transition temperature of 54°C., a number average molecular weight of 5200, a hydroxyl value of 70mmKOH/g and an acid value of 6 mmKOH/g.

Preparation Examples 22 through 27

By using ingredients in the amount shown in Tables 27 and 28,organic-inorganic composite solutions were obtained in the same methodas described in Preparation Example 21.

TABLE 27 Preparation Example 21 22 23 24 25 initial xylene 33.3 33.333.3 33.3 33.3 (parts by isobutylacetate 33.3 33.3 33.3 33.3 33.3weight) dropping methylmethacrylate 61.0 63.0 70.0 21.0 61.5 (parts bybutylacrylate 19.0 8.0 10.0 6.0 13.5 weight) cyclohexylmethacrylate — —— 51.0 51.0 glycidylmethacrylate — — — — 5.0 2-hydroxyethylmethacrylate19.0 28.0 19.0 21.0 19.0 methacrylic acid 1.0 1.0 1.0 1.0 1.0 ABMBN 1.71.7 0.9 1.7 1.7 additional ABMBN 0.2 0.2 0.2 0.2 0.2 (parts by isobutylacetate 2.0 2.0 2.0 2.0 2.0 weight) silica sol Preparation Example 1736.9 — — — 36.9 (parts by Preparation Example 18 — 36.9 — — — weight)Preparation Example 19 — — 73.8 — — Preparation Example 20 — — — 55.6 —total (parts by weight) 207.4 207.4 243.5 226.1 207.4 non-volatilematerial conc. (% by weight) 56.2 56.5 55.0 55.5 56.4 organic- glasstransition temperature (° C.) 54 74 78 76 64 inorganic number averagemolecular weight 5200 5500 13000 5000 5100 composite hydroxyl value(mgKOH/g) 70 104 62 72 70 properties acid value (mgKOH/g) 6 6 5 5 6

TABLE 28 Preparation Example 26 27 initial xylene 33.3 33.3 (parts byisobutylacetate 33.3 33.3 weight) dropping methylmethacrylate 21.0 21.0(parts by butylacrylate 6.0 6.0 weight) cyclohexylmethacrylate 51.0 51.0glycidylmethacrylate — — 2-hydroxyethylmethacrylate 21.0 21.0methacrylic acid 1.0 1.0 ABMBN 5.0 0.2 additional ABMBN 0.2 0.2 (partsby isobutyl acetate 2.0 2.0 weight) silica sol Preparation Example 17 —— (parts by Preparation Example 18 — — weight) Preparation Example 1955.6 55.6 Preparation Example 20 — — total (parts by weight) 229.4 224.6non-volatile material conc. (% by weight) 55.8 56.0 organic- glasstransition temperature (° C.) 76 76 inorganic number average molecularweight 2300 20000 composite hydroxyl value (mg KOH/g) 72 72 propertiesacid value (mg KOH/g) 5 5

Examples 33 through 40

Coating compositions were prepared in the compounding rate shown inTables 29 and 30 in the same method as described in Example 1 and curedfilms were formed on the test panels. Baking conditions and forceddrying conditions at forming cured films were shown in Tables 29 and 30and the cured film properties were shown in Tables 31 and 32.

TABLE 29 Example 33 34 35 36 37 compounding organic- kind (PreparationPrep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate inorganicExample) 21 22 23 24 23 (parts by composite formulation weight 78.9 63.282.8 74.6 82.8 weight) solution silica sol kind Prep. Ex. Prep. Ex.Prep. Ex. Prep. Ex. Prep. Ex. 17 18 19 20 19 formulation weight 5.2 20.00.4 0.5 0.4 curing DURANATE THA-100 11.0 — 11.8 — 11.8 agent DURANATE24A-100 — 11.8 — — — DISMODUR BL-3175 — — — 19.9 — solvent cyclohexanone1.9 2.0 2.0 2.0 2.0 additive TINUVIN 900 0.8 0.8 0.8 0.8 0.8 TINUVIN 2920.2 0.2 0.2 0.2 0.2 BYK-358 1.0 1.0 1.0 1.0 1.0 curing SCAT-8 (10% by —— — 1.0 — catalyst weight solution) SCAT-8 (1% by 1.0 1.0 1.0 — 1.0weight solution) total 100.0 100.0 100.0 100.0 100.0 NCO/OH (mole ratio)1.0 1.0 1.2 1.0 1.0 silica sol non-volatile matter/total non-volatile 1525 20 15 20 matter (percent by weight) baking or forced dryingtemperature (° C.) 120 140 80 150 room condition temp. time (minutes) 2520 30 25 240

TABLE 30 Example 38 39 40 compounding organic- kind (Preparation Prep.Prep. Prep. rate inorganic Example) Ex. Ex. Ex. (parts by composite 2526 27 weight) solution formulation weight 78.9 74.6 82.8 silica sol kindPrep. Prep. Prep. Ex. Ex. Ex. 17 19 19 formulation weight 5.2 0.5 0.4curing DURANATE THA- 11.0 — 11.8 agent 100 DURANATE 24A- — — — 100DISMODUR BL- — 19.9 — 3175 solvent cyclohexanone 1.9 2.0 2.0 additiveTINUVIN 900 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.2 BYK-358 1.0 1.0 1.0curing SCAT-8 (10% by — 1.0 — catalyst weight solution) SCAT-8 (1% by1.0 — 1.0 weight solution) total 100.0 100.0 100.0 NCO/OH (mole ratio)1.0 1.0 1.0 silica sol non-volatile matter/total non-volatile 15 15 16matter (percent by weight) baking or forced drying temperature (° C.)120 150 room condition temp. time (minutes) 25 25 600

TABLE 31 Example 33 34 35 36 37 operation efficiency atomization ⊚ ⊚ ⊚ ⊚⊚ in coating process transfer efficiency ⊚ ⊚ ⊚ ⊚ ⊚ cured 60° gloss 93 9190 91 90 film distinctness of image ∘ ∘ ∘ ∘ ∘ properties accelerated1000 hours 100 100 100 100 100 weathering test 2000 hours 99 98 97 97 97gloss retention (%) 3000 hours 95 95 97 95 96 4000 hours 93 93 95 93 955000 hours 93 92 94 91 94 6000 hours 92 91 93 90 92 moisture resistance∘ ∘ ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ ∘ ∘ acid resistance ∘ ∘ ∘ ∘ ∘alkali resistance ∘ ∘ ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ ∘ ∘ resistance red∘ ∘ ∘ ∘ ∘ pencil hardness (breaking) 3H 4H 4H 4H 3H pencil hardness(cloud) F 2H H H H adhesive property ∘ ∘ ∘ ∘ ∘ appearance of a thickcoated ∘ ∘ ∘ ∘ ∘ stain property in atomospheric 1.3 0.7 1.0 1.1 0.9exposure (ΔL) stain after removing stains (ΔL) 0.2 0.1 0.1 0.0 0.1

TABLE 32 Example 38 39 40 operation efficiency atomization ⊚ ⊚ ∘ incoating process transfer efficiency ⊚ ⊚ ∘ cured 60° gloss 91 93 87 filmdistinctness of image ∘ ∘ ∘ properties accelerated 1000 hours 99 99 100weathering test 2000 hours 97 97 98 gloss retention (%) 3000 hours 95 9496 4000 hours 94 94 95 5000 hours 93 91 94 6000 hours 91 89 91 moistureresistance ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ acid resistance ∘ ∘ ∘alkali resistance ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ resistance red ∘ ∘ ∘pencil hardness (breaking) 3 H 3 H 4 H pencil hardness (cloud) F H 2 Hadhesive property ∘ ∘ ∘ appearance of a thick coated ∘ ∘ ∘ stainproperty in atomospheric 1.3 1.2 1.3 exposure (ΔL) stain after removingstains (Δ 0.2 0.2 0.0 L)

Example 41

By mixing and dispersing 58.3 parts by weight of titanium oxide (DUPONTTITANIUM R-960, a product of Dupont Co.), 34.6 parts by weight of theorganic-inorganic composite solution obtained in Preparation Example 21and 7.1 parts by weight of cyclohexanone with zircon beads as media in amotor mill (a product of Eiger Japan Co. ) at 3,000 rpm for 40 minutes,a pigment-dispersed coating composition solution was prepared.

And, 42.6 parts by weight of the pigment-dispersed coating compositionsolution, 35.3 parts by weight of the organic-inorganic compositesolution obtained in Preparation Example 21, 13.0 parts by weight of thesurface-treated silica sol obtained in Preparation Example 17, 0.2 partsby weight of TINUVIN 292, 1.0 parts by weight of BYK-358, 1.0 parts byweight of 1 percent by weight solution of SCAT-8 and 6.9 parts by weightof DURANATE THA-100 were mixed under stirring and a coating compositionwas prepared.

Examples 42 through 45

Coating compositions were prepared in the compounding rate shown inTable 33 in the same method as described in Example 38 and cured filmswere formed on the test panels. Baking conditions and forced dryingconditions at forming cured films were shown in Table 33 and the curedfilm properties were shown in Table 34.

TABLE 33 Example 41 42 43 44 45 pigment-dispersed titanium oxide 58.358.3 58.3 58.3 58.3 organic-inorganic organic-inorganic Prep. Ex. Prep.Ex. Prep. Ex. Prep. Ex. Prep. Ex. composite solution composite solution21 22 23 24 23 formulation weight 34.6 34.6 40.6 37.7 40.6 cyclohexanone7.1 7.1 1.1 4.0 1.1 sub total 100.0 100.0 100.0 100.0 100.0 compoundingpigment-dispersed organic- 42.6 35.9 40.2 42.6 40.2 rate inorganiccomposite solution (parts by described above weight) organic- kind(Prep. Ex.) Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. inorganic21 22 23 24 23 composite formulation amount 35.3 26.7 36.7 32.3 36.7solution silica sol kind (Prep. Ex.) Prep. Ex. Prep. Ex. Prep. Ex. Prep.Ex. Prep. Ex. 17 18 19 20 19 formulation amount 13.0 27.9 13.3 10.0 13.3curing DURANATE THA-100 6.9 — 7.6 — 7.6 agent DURANATE 24A-100 — 7.3 — —— DISMODUR BL-3175 — — — 12.9 — additives TINUVIN 292 0.2 0.2 0.2 0.20.2 BYK-358 1.0 1.0 1.0 1.0 1.0 curing SCAT-8 (10% by — — — 1.0 —catalyst weight solution) SCAT-8 (1% by 1.0 1.0 1.0 — 1.0 weightsolution) total 100.0 100.0 100.0 100.0 100.0 NCO/OH (mole ratio) 1.01.0 1.2 1.0 1.2 silica sol non-volatile matter/total non- 15 25 20 15 20volatile matter (% by weight) baking or forced drying temperature (° C.)120 140 80 150 room condition temp. time (minutes) 25 20 30 25 240

TABLE 34 Example 41 42 43 44 45 operation efficiency atomization ⊚ ⊚ ⊚ ⊚⊚ in coating process transfer efficiency ⊚ ⊚ ⊚ ⊚ ⊚ cured 60° gloss 90 8888 89 88 film distinctness of image ◯ ◯ ◯ ◯ ◯ properties accelerated1000 hours 100 100 100 100 100 weathering test 2000 hours 98 97 98 99 97gloss retention (%) 3000 hours 97 94 96 97 95 4000 hours 94 93 94 93 935000 hours 91 91 91 92 92 6000 hours 89 90 90 91 90 moisture resistance◯ ◯ ◯ ◯ ◯ xylene rubbing resistance ◯ ◯ ◯ ◯ ◯ acid resistance ◯ ◯ ◯ ◯ ◯alkali resistance ◯ ◯ ◯ ◯ ◯ oil ink stain black ◯ ◯ ◯ ◯ ◯ resistance red◯ ◯ ◯ ◯ ◯ pencil hardness (breaking) 3H 4H 4H 4H 3H pencil hardness(cloud) F 2H H 2H H adhesive property ◯ ◯ ◯ ◯ ◯ appearance of a thickcoated ◯ ◯ ◯ ◯ ◯ stain property in atomospheric 1.4 0.7 0.9 1.3 1.1exposure (ΔL) stain after removing stains (Δ 0.2 0.1 0.0 0.1 0.1 L)

Examples 46 through 48

Coating compositions were prepared in the compounding rate shown inTable 35 in the same method as described in Example 17 and cured filmswere formed on the test panels. Baking conditions and forced dryingconditions at forming cured films were shown in Table 35 and the curedfilm properties were shown in Table 36.

TABLE 35 Example 46 47 48 compounding organic- kind (Preparation Prep.Prep. Prep. rate inorganic Example) Ex. Ex. Ex. (parts by composite 2122 23 weight) solution formulation weight 71.6 75.0 73.8 silica sol kind(Preparation Prep. Prep. Prep. Example) Ex. Ex. Ex. 17 18 20 formulationweight 5.3 10.3 12.1 curing UVAN 220 19.1 — — agent UVAN 122 — 10.6 —CYMEL 370 — — 10.2 solvent cyclohexanone 1.9 2.0 1.9 additive TINUVIN900 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.2 BYK-358 1.0 1.0 1.0 curingNacure 4054 0.1 0.1 — catalyst total 100.0 100.0 100.0 acryl/melamine(weight ratio of non-volatile 75/25 85/15 80/20 matter) silica solnon-volatile matter/total non-volatile 15 20 25 matter (percent byweight) baking or forced drying temperature (° C.) 140 135 150 conditiontime (minutes) 30 25 25

TABLE 36 Example 46 47 48 operation efficiency atomization ⊚ ⊚ ⊚ incoating process transfer efficiency ⊚ ⊚ ⊚ cured 60° gloss 89 88 88 filmdistinctness of image ∘ ∘ ∘ properties acclerated 1000 hours 99 100 99weathering test 2000 hours 97 98 97 gloss retention (%) 3000 hours 94 9597 4000 hours 93 94 95 5000 hours 93 92 94 6000 hours 92 92 93 moistureresistance ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ acid resistance ∘ ∘ ∘alkali resistance ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ resistance red ∘ ∘ ∘pencil hardness (breaking) 3 H 4 H 4 H pencil hardness (cloud) H H Hadhesive property ∘ ∘ ∘ appearance of a thick coated ∘∘ ∘ stain propertyin atomospheric 1.4 0.8 0.6 exposure (ΔL) stain after removing stains (Δ0.1 0.1 0.0 L)

Examples 49 through 51

Coating compositions were prepared in the compounding rate shown inTable 37 in the same method as described in Example 41 and cured filmswere formed on the test panels. Baking conditions and forced dryingconditions at forming cured films were shown in Table 37 and the curedfilm properties were shown in Table 38.

TABLE 37 Example 49 50 51 pigment-dispersed titanium oxide 58.3 58.358.3 organic-inorganic organic-inorganic composite Prep. Prep. Prep.composite solution Ex. Ex. Ex. solution 21 22 24 formulation weight 34.634.6 37.7 cyclohexanone 7.1 7.1 1.1 sub total 100.0 100.0 100.0compounding pigment-dispersed organic- 41.1 37.6 35.6 ratio inorganiccomposite solution (parts by described above weight) organic- kind(Preparation Prep. Prep. Prep. inorganic Example) Ex. Ex. Ex. composite21 22 24 solution formulation weight 32.4 35.4 33.6 silica sol untreatedsilica sol Prep. Prep. Prep. Ex. Ex. Ex. 17 18 20 Preparation Ex. 1512.8 18.8 23.1 curing UVAN 220 12.4 — — agent UVAN 122 — 6.9 — CYMEL 370— — 6.5 additive TINININ 292 0.2 0.2 0.2 BYK-358 1.0 1.0 1.0 curingNacure 4054 0.1 0.1 — catalyst total 100.0 100.0 100.0 acryl/melamine(weight ratio of non-volatile 75/25 85/15 80/20 matter) silica solnon-volatile matter/total non-volatile 15 20 25 matter (percent byweight) baking or forced drying temperature (° C.) 140 135 150 conditiontime (minutes) 30 25 25

TABLE 38 Example 49 50 51 operation efficiency atomization ⊚ ⊚ ⊚ incoating process transfer efficiency ⊚ ⊚ ⊚ cured 60° gloss 86 85 86 filmdistinctness of image ∘ ∘ ∘ properties accelerated 1000 hours 98 100 99weathering test 2000 hours 97 97 98 gloss retention (%) 3000 hours 95 9697 4000 hours 93 95 94 5000 hours 92 95 91 6000 hours 90 92 90 moistureresistance ∘ ∘ ∘ xylene rubbing resistance ∘ ∘ ∘ acid resistance ∘ ∘ ∘alkali resistance ∘ ∘ ∘ oil ink stain black ∘ ∘ ∘ resistance red ∘ ∘ ∘pencil hardness (breaking) 4 H 4 H 4 H pencil hardness (cloud) H H 2 Hadhesive property ∘ ∘ ∘ appearance of a thick coated ∘ ∘ ∘ stainproperty in atomospheric 1.2 0.7 0.7 exposure (ΔL) stain after removingstains (Δ 0.1 0.0 0.1 L)

Preparation Example 28

A dispersing component of silica sol dispersed in a solvent was preparedin the same method as described in Preparation Example 17, except thatthe surface treatment with a silane coupling agent was not carried outin Prepatation Example 17. The kind and the amount of ingredients usedwere shown in Table 39.

TABLE 39 Preparation Example 28 water-based silica sol SNOWTEX O 225initial solvent isopropyl alcohol 78.8 continuous dropping solventisopropyl alcohol 1500.0 weight of middle stage (parts by weight) 280water content of middle stage (% by weight) solvent of second stagecyclohexanone 450.0 yield (parts by weight) 100.0 non-volatile matter (%by weight) 45.0 water content (% by weight) 0.1

Comparison of storage stability

The storage stabilities of the dispersing components of silica solobtained in Preparation Example 17 to 20 were compared with that of thedispersing component of silica sol obtained in Preparation Example 28.The results were shown in Table 40.

TABLE 40 dispersing component of silica sol storage stabilityPreparation Example 17 no change Preparation Example 18 no changePreparation Example 19 no change Preparation Example 20 no changePreparation Example 28 gellation after 3 days

Example 52

Cationic electrodeposition coat AQUA No. 4200® (a product of NOFCORPORATION) was applied by electrodeposition to a soft steel platetreated with zinc phosphate in the amount to form a film having driedthickness of 20 μm and the coated plate was baked at 175° C. for 25minutes. Intermediate coat EPICO No. 1500CP Sealer® (a product of NOFCORPORATION) was applied to the prepared plate by air spraying in theamount to form a film having dried thickness of 40 μm and the plate wasbaked at 140° C. for 30 minutes. Silver metallic base coatingcomposition, BELCOAT No. 6000® (a product of NOF CORPORATION) wasapplied to the intermediated coat by air spraying in 2 stages withinterval of 1 minutes 30 seconds in the amount to form a film havingdried thickness of 15 μm and the coated pieces were set at 20° for 3minutes to obtain a test panel. Further, the coating composition ofExample 33 were diluted with thinner (xylene) to a viscosity requiredfor spraying (25 seconds at 20° C. by Ford cup No. 4) and applied to thetest panel prepared before by air spraying in the amount to form a filmhaving dried thickness of 40 μm and the test piece was baked at thecuring condition of 80° C. for 30 minutes to obtain a test piece havingmulti layers. Compounding rate of the coating composition, bakingcondition and forced drying condition at forming cured films were shownin Table 41 and the cured film properties were shown in Table 42.

Example 53

The test piece was formed in the same method as described in Example 52,except that the coating composition of Example 46 was used instead ofthe coating composition of Example 33. Compounding rate of the coatingcomposition, baking condition and forced drying condition at formingcured films were shown in Table 42.

Example 54

Cationic electrodeposition coat AQUA No. 4200® (a product of NOFCORPORATION) was applied by electrodeposition to a soft steel platetreated with zinc phosphate in the amount to form a film having driedthickness of 20 μm and the coated plate was baked at 175° C. for 25minutes. Intermediate coat EPICO No. 1500CP Sealer® (a product of NOFCORPORATION) was applied to the prepared plate by air spraying in theamount to form a film having dried thickness of 40 μm and the plate wasbaked at 140° C. for 30 minutes. Silver metallic base coatingcomposition, BELCOAT No. 6000® (a product of NOF CORPORATION) wasapplied to the intermediated coat by air spraying in 2 stages withinterval of 1 minute 30 seconds in the amount to form a film havingdried thickness of 15 μm and the coated pieces were set at 20° C. for 3minutes. Further, the clear coating composition of an acrylicresin/aminoplast resin coating composition, BELCOAT No. 6000 CLEAR COAT®(a product of NOF CORPORATION, ratio by weight of acrylic resin toaminoplast resin: 70/30) was applied by air spraying in the amount toform a film having dried thickness of 30 μm and the plate was baked at140° C. for 30 minutes. Further more, as an over-clear coatingcomposition, the coating composition of Example 35 were diluted withthinner (xylene) to a viscosity required for spraying (25 seconds at 20°C. by Ford cup No. 4) and applied to the test panel prepared before byair spraying in the amount to form a film having dried thickness of 10μm and the test piece was baked at the curing condition of 80° C. for 30minutes to obtain a test piece having multi layers. Compounding rate ofthe coating composition, baking condition and forced drying condition atforming cured films were shown in Table 41 and the cured film propertieswere shown in Table 42.

Example 55

The test piece was formed in the same method as described in Example 54,except that the coating composition of Example 48 was used instead ofthe coating composition of Example 35. Compounding rate of the coatingcomposition, baking condition and forced drying condition at formingcured films were shown in Table 41 and the cured film properties wereshown in Table 42.

TABLE 41 Example 52 53 54 55 compounding organic- kind (PreparationPrep. Ex. Prep. Ex. Prep. Ex. Prep. Ex. rate inorganic Example) 21 21 2323 (parts by composite formulation weight 78.9 71.6 82.8 73.8 weightsolution silica sol kind (Preparation Prep. Ex. Prep. Ex. Prep. Ex.Prep. Ex. Example) 17 17 19 20 formulation weight 5.2 5.3 0.4 12.1curing DURANATE THA-100 11.0 — 11.8 — agent DURANATE 24A-100 — — — —DESMODUR BL-3175 — — — — UVAN 220 — 19.1 — — UVAN 122 — — — — CYMEL 370— — — 10.2 solvent cyclohexanonel 1.9 1.9 2.0 1.9 additives TINUVIN 9000.8 0.8 0.8 0.8 TINUVIN 292 0.2 0.2 0.2 0.2 BYK-358 1.0 1.0 1.0 1.0curing SCAT-8 — — — — catalyst (10% by weight solution) SCAT-8 1.0 — 1.0— (1% by weight solution) Nacure 4054 — 0.1 — total 100.0 100.0 100.0100.0 NCO/OH (mole ratio) 1.0 — 1.2 — acryl/melamine (weight ratio ofnon-volatile — 75/25 — 80/20 matter) silica sol non-volatilematter/total non-volatile 15 15 20 25 matter (percent of weight) bakingor forced drying condition temperature 80 140 80 150 time (minutes) 2530 30 25

TABLE 42 Example 52 53 54 55 operation efficiency atomization ⊚ ⊚ ⊚ ⊚ incoating process transfer efficiency ⊚ ⊚ ⊚ ⊚ cured 60° gloss 92 93 92 93film distinctness of image ◯ ◯ ◯ ◯ properties accelerated 1000 hours 100100 99 100 weathering test 2000 hours 97 98 97 98 gloss retention (%)3000 hours 96 95 96 97 4000 hours 92 94 92 94 5000 hours 91 91 91 916000 hours 90 90 89 90 moisture resistance ◯ ◯ ◯ ◯ xylene rubbingresistance ◯ ◯ ◯ ◯ acid resistance ◯ ◯ ◯ ◯ alkali resistance ◯ ◯ ◯ ◯ oilink stain black ◯ ◯ ◯ ◯ resistance red ◯ ◯ ◯ ◯ pencil hardness(breaking) 3H 4H 4H 4H pencil hardness (cloud) F F F F adhesive property◯ ◯ ◯ ◯ appearance of a thick coated ◯ ◯ ◯ ◯ stain property inatomospheric 1.3 1.4 1.0 0.8 exposure (ΔL) stain after removing stains(Δ 0.1 0.1 0.0 0.1 L)

The coating compositions of the present invention comprise ceramicingredients and give the cured films having excellent weatheringresistance, light resistance, stain resistance, stain removing property,chemical resistance, moisture resistance and appearance and is excellentin environment friendliness and safety.

What is claimed is:
 1. A process for preparing a coating compositiondispersing component comprising a silica sol dispersed in a solvent, theprocess consisting essentially of: (a) dehydrating an aqueous silica solby adding a compound consisting essentially of at least onewater-soluble azeotropic solvent selected from the group consisting ofan alcohol, a carboxylic acid ester and a cyclic ether to the aqueoussilica sol to form an azeotropic mixture and optionally adding awater-insoluble solvent, and carrying out an azeotropic distillation andthen (b) surface-treating the resultant dispersing component from step(a) with at least one silane coupling agent selected from the groupconsisting of methyltrimethoxysilane, dimethyldimethoxysilane,γ-glycidoxypropyltrimethoxysilane andγ-methacryloyloxypropyltrimethoxysilane.
 2. The process as claimed inclaim 1, wherein the silane coupling agent is selected from the groupconsisting of methyltrimethoxysilane and dimethyldimethoxysilane.
 3. Theprocess as claimed in claim 1, wherein the silane coupling agent is inan amount of 1 to 40 percent by weight based on the nonvolatile mattercontained in the silica sol.
 4. The process as claimed in claim 1,wherein the silane coupling agent is in an amount of 5 to 30 percent byweight based on the nonvolatile matter contained in the silica sol. 5.The process as claimed in claim 1, wherein the water-soluble azeotropicsolvent is selected from the group consisting of ethanol,n-propylalcohol, i-propylalcohol, n-butylalcohol, i-butylalcohol,sec-butylalcohol, t-butylalcohol, methylcellosolve, ethylcellosolve,ethyleneglycolmonomethylether, ethyleneglycolmonoethylether,ethyleneglycolmono-n-propylether, ethyleneglycolmonobutylether,diethyleneglycolmonomethylether, diethyleneglycolmonoethylether,diethyleneglycolmonobutylether, 3-methyl-3-methoxybutanol,propyleneglycolmonomethylether, ethyleneglycol, propyleneglycol,methylacetate, ethylacetate and 1,4-dioxane.
 6. The process as claimedin claim 5, wherein the water-soluble azeotropic solvent is usedtogether with a water-insoluble solvent selected from the groupconsisting of benzene, xylene, toluene, cyclohexanone, diphenylether anddibutylether.
 7. The process as claimed in claim 5, wherein thedehydrating is carried out at a temperature of 40 to 80° C.
 8. Theprocess as claimed in claim 7, wherein the surface-treating is carriedout at a temperature of 40 to 80° C.
 9. The process as claimed in claim7, wherein the surface-treating is carried out at a temperature of 30 to90° C.
 10. The process as claimed in claim 1, wherein the dehydrating iscarried out at a temperature of 30 to 100° C.
 11. The process as claimedin claim 9, wherein the surface-treating is carried out at a temperatureof 20 to 100° C.
 12. The process as claimed in claim 1, wherein afterthe dehydrating, the silica sol is dispersed in the azeotropic solventand has a water content of not more than 2 percent by weight.
 13. Theprocess as claimed in claim 13, wherein after the dehydrating, thesilica sol is dispersed in the azeotropic solvent and has a watercontent of not more than 1 percent by weight.
 14. The process as claimedin claim 1, wherein after the surface-treating, the silica sol isdispersed in the azeotropic solvent and has a water content of not morethan 1 percent by weight.
 15. The process as claimed in claim 1, whereinafter the surface-treating, the silica sol is dispersed in theazeotropic solvent and has a water content of not more than 0.5 percentby weight.
 16. The process as claimed in claim 1, wherein after thedehydrating, the dispersing component of the silica sol is dispersed inthe water-soluble azeotropic solvent in a concentration of not more than55 weight percent as a nonvolatile content.
 17. The process as claimedin claim 16, wherein the dispersing component of the silica sol isdispersed in the water soluble azeotropic solvent in a concentration of25 to 55 weight percent as nonvolatile content.
 18. A process-forpreparing a coating composition dispersing component comprising a silicasol dispersed in a solvent, the process consisting essentially of: (a)dehydrating an aqueous silica sol by adding a compound consistingessentially of at least one water-soluble azeotropic solvent selectedfrom the group consisting of an alcohol, a carboxylic acid ester and acyclic ether to the aqueous silica sol to form an azeotropic mixture,and optionally adding a water-insoluble solvent, and carrying out anazeotropic distillation and then (b) surface-treating the resultantdispersing component from step (a) with at least one silane couplingagent selected from the group consisting of methyltrimethoxysilane,dimethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane andγ-methacryloyloxypropyltrimethoxysilane, and then (c) adding a solventother than water and other than the water-soluble azeotropic solvent andremoving the water-soluble azeotropic solvent.
 19. The process asclaimed in claim 18, wherein the solvent other than water and other thanthe water-soluble azeotropic solvent is at least one solvent selectedfrom the group consisting of an alcohol, acetone, methylethylketone,methylisobutylketone, cyclohexanone, dimethylacetoamide anddimethylformamide.